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 Frequently Asked Questions

Recommended Books:

This is the rec.models.railroad list of Frequently Asked Questions (FAQ). Contributors are acknowledged at the end of the file.


Q. What does prototype mean?

It has several meanings, but typically refers to real-world trains (in contrast to scale models of them). Also called 12"-to-the-foot. However, it can also mean the first item in a series, which meaning is often applied to equipment built as tests by real railroads.

Q. What is the difference between scale and gauge?

Scale is the ratio between the model and the prototype; for example, N scale is 1/160th of the size of the real world. Gauge is the distance between the inside faces of the two rails. Standard gauge in the United States and most of the British Commonwealth is 4'8.5", with 3' and 2' as fairly common narrow gauges. Note that this standardization did not exist when railroads were first being built, causing excessive delays when people and freight had to transfer between railroads with incompatible gauges.

Q. What sizes (actually scales) do models come in?

The standard scales, listed in approximate order of popularity, are:

  • HO1/87 (actually 3.5mm to the foot, or 1/87.1)
  • N 1/160 (1/152, 2mm per foot in the UK)
  • O 1/48 (but see below)
  • G 1/22.5 or 1/24, or whatever the manufacturer decides
  • S 1/64
  • OO 1/76.2 (4 mm to the foot, mostly used in the UK)
  • Z 1/220
  • No. 1 1/32
  • TT 1/120 (common scale in the former GDR, only produced by Zeuke in Berlin)

By design, this list only includes the common scales which most beginning modelers are likely to run into. There are many other scales and variations in scales (for example, OO is slightly different in the US but virtually nobody uses it here), but this is a list of _frequently_ asked questions, not an exhaustive (and thus difficult to read) compilation of every scale known to exist.

People build models in other (typically larger) scales, but they tend to be mostly scratchbuilt. 1/8th scale (1.5" to the foot) is a common size for outdoor models large enough to carry people.

In O scale, track has been traditionally laid to scale 5'0" gauge instead of standard. O scale modelers divide into four groups according to how they handle the discrepancy between gauge and scale:
a. most O scalers live with the discrepancy.
b. some model at 1/45 scale, keeping the traditional O gauge.
c. some model at 1/48 (known as Proto:48) and narrow the traditional guage to standard, but these models will not interoperate with the first two groups.
d. European modellers use 7mm/ft, with 32mm track gauge (the fine scale folks use 33mm). 32mm gives a scale gauge just less than 4ft 7in, and 33mm gives marginally over 4ft 8.5in.

Also, there is a sharp distinction between 0-scale trains/layouts, and O-gauge tinplate trains. The trains made by Lionel and other toy manufacturers are called "tinplate" (for historical reasons) and run on 3-rail track. The original track has a rounded head and very tall rails (hence the term "hi-rail" is also used), although much more prototypical track is now made for 3-rail locomotives. They typically use AC propulsion power. Confusion arises because both use "0 gauge", 1 1/4" between the rails. 0-scale models are built to 1/4" scale and typically are models of particular prototypes. Tinplate models are typically made to a somewhat smaller scale and are often 'generic', i.e., they generally represent no one prototype, but rather give the general impression of a number of real trains. Some more expensive tinplate trains are prototypical, and this is a increasing trend.

Q. What is HOn3 scale?

This is HO scale equipment (1/87th) running on narrow gauge rails spaced 3 feet apart. Narrow gauge in other scales is represented in a similar fashion. There are similar notations for models whose gauge is based on non-English measurements, such as HOm (HO scale, one-meter gauge) and HOe (HO scale, 0.75 meter guage), as well as HOn30, which indicates 30" (2.5') gauge.

Q. What do scratchbuilt and kitbashed mean?

These terms have somewhat vague boundaries, but basically indicate that a model was not built directly as suggested from a kit. Scratchbuilt usually means starting with wood, cardboard, plastic, or other basic materials and then designing and cutting all of the necessary pieces. Kitbashing refers to starting with one or more commercial kits but assembling the pieces in a different fashion, often adding other material or recutting the original pieces. Both of these methods allow you to build models for which no kits are available.

Q. What is a traction layout?

The term as used in model railroading refers to streetcars, trolleys, and electric-powered interurban lines.

Q. What is hydrocal?

This a plaster product commonly used for creating terrain. The easiest sources seem to be model railroad stores, since I've yet to find a building supply store that has any idea what I want. The advantage of hydrocal is that it is very strong once it sets up, as opposed to plaster which needs something underneath it to support it even after it dries. Hydrocal needs support while setting but cardboard strips do just fine. Regular plaster requires chicken wire and wood supports for shaping -- it's a lot more work, and a lot more weight.

Q. What is a rerail frog?

A. A rerail-frog is a kind of a metal ramp thing that is used to help re-rail a car or engine that has gone off the track but not wandered too far away or overturned. It is temporarily spiked, wedged or clamped next to the rail at the wheel that needs to be lifted back over the rail and then the car is pushed or pulled by the engine to get the wheel to ride up over the ramp and back onto the track. Typically in branch line service you would see these dangling from the sides of the tender along with some chains or cables. More tools including jacks, levers, wrenches for splice bolts and so on might be kept in the caboose or stashed on the engine.

Q. What is a winterization hatch?

A. A hatch or cover used to cover up or close off the normal ventilation for oil-coolers, air-coolers or excess fan/radiator area for exterme cold weather.

Q. What is a Maintenance of Way (MOW) car?

These are "non-revenue" cars (so-called because they are not used to service paying customers) used by the railroad for upkeep on the track, roadbed, and surrounding infrastructure. These are typically older or damaged cars no longer suitable for high-speed work. They include things such as cranes, ballast cars (converted hoppers used to spread gravel between the ties), tie cars, rail cars, etc. Since they are usually fabricated by the shop crew out of whatever is available they come in a wider range of styles than ordinary cars.

Train sets

Q. What should I buy as a gift for somebody who is new to the hobby?

(This answer is tailored to HO, since that's what I know about)

The cheap packaged sets make by Bachman and Life-Like are not a good way to get started in the hobby. The equipment is cheaply made and as a consequence will tend to stall and derail frequently, and is also likely to break early. While you'll spend slightly more by buying individual items, you can assemble a starter set from better equipment and still spend under $100. The following list is a suggestion of specific items which will make a nice set for somebody new to the hobby, either adult or 8+ year old child.

- Athearn diesel locomotive with "superpower" drive. They make a wide range of locomotives, so pick whatever looks good. The "superpower" drive means it has flywheels and a heavy weight, both of which make it run better, and it only runs about $5 more than the base models. $26-33

- Several Athearn car kits [very easy to assemble]. They make both freight and passenger, so pick whetever interests you (or the recipient). Freight cars are $4-5, passenger $7.

- MRC Tech II Railpower 1400 power pack. You'll need a few feet of wire and an Atlas terminal track section to attach it to the track. $41 (+ $2 for the terminal)

- Enough Atlas Nickel-silver track to make an oval. 2 packs of 18" curves and 1 pack of straight will do. $3.50/pack

- A copy of Model Railroader magazine. The December issue always has articles aimed at newcomers, but most issues will have introductory-level articles. $3.95

The stuff above will make the minimum starter set, for just over $100, depending on the engine and cars purchased. If you want to go for something slightly more advanced consider adding some of the following items:

- 2 or so Atlas Snap turnouts (track switches), $6 each unpowered. Get both left and right handed.

- An Atlas pier set combined with one of their bridge kits. To make an over-under figure-8 layout you'll also need another package of curved track. $10 for the pier set, bridges are $4-10.

- Some building kits. The Atlas passenger station kit is a classic kit which is well manufactured and can be built into a nice looking kit with a little time. Probably not too good for a young child since it has lots of parts. Kits run $5-15 for simpler ones, much more in some cases. Include some Testor's liquid glue [in a cubical glass bottle. The thicker version in a orange/white tube is junk] (also not great around young children; for that matter.) and an X-Acto knife.

I have picked these items from personal experience - there are undoubtedly equally good choices from other manufacturers. Everything listed here should be available at most hobby stores which carry train equipment. Your best bet is to find a hobby store which specializes in model railroads and tell them you want to assemble something like this. They should be able to show you the items listed here as well as alternatives which you might prefer.

Q. What should I buy if I'm willing to spend more money?

Higher quality locomotives can be purchased from Atlas, Stewart, and KATO (who make the mechanisms for some other brands as well). These models run very well, have more accurate and refined details, and will cost about $100 for a single locomotive. Life-Like has a premium line called "Proto 2000" and Bachman has one called "Spectrum" which offer medium level products in the $50-75 range.

In addition to Athearn, MDC (Model Die Casting, also known as Roundhouse) makes good quality kits in the $10-25 range, and they are about as easy to find as Athearn. They make more of the modern equipment than does Athearn.

Peco makes better quality track switches, for about $15 unpowered. They have a spring which keeps the switch rails firmly in the selected position and an under-table power unit which is easy to install (although you have to cut a hole in the table). They come in "Electrofrog" and "Insulfrog" versions - the Electrofrog ones are "power routing," which means that the track power only flows in the direction the switch is set. This can make it much easier to wire stub sidings in a block scheme, since you don't need a separate block for the siding. Insulfrog ones work the way most other switches do.

Q. What if I just won the lottery?

Brass models are regularly imported by a small collection of companies based in Japan and South Korea. These are limited run (~100 units) models of specific prototypes, hand-made from brass. They are usually delivered unpainted but some runs offer factory painted units at an extra cost. The majority of these models are of locomotives, with steam more abundant than diesel or electric. Passenger cars and cabooses are also fairly common, with occasional freight and maintenance-of-way cars offered. The main appeal of these models is that well-made ones will be exact models of particular prototypes with a high level of detail. They also come with high quality drives, something quite difficult to find in cheaper steam locomotives.

The cheapest brass locomotives in HO are offered by Sunset Ltd., with most models in the $200-300 range. They are reportedly good runners with a fairly low level of detail. Highly detailed models are offered by the other importers, with steam prices in the $450-1000+ range, diesels in the $200-400+ range. O scale models can run twice as much as these prices. The best bet is to find either a local dealer or a reputable mail-order importer who can advise you on what looks good for the money.

Most of these items are sold by advance reservation, so by the time the model actually arives there may not be any left for sale. The models are advertised in advance of production so that you can place an order in time. Used models can be purchased and can be a good value if purchased from a reputable dealer who is honest about the quality.

Q. How come the affordable suggestions only include diesel engines?!?

In general, steam engines are more expensive than their diesel counterparts. For example, the cheapest HO "ready-to-run" steam engines cost about $100. If you are the type who likes to build kits, the cheapest steam engine kit costs about $70 dollars. Below is a short description of several popular steam engine brands. The prices in square brackets are mail order prices provided by a second contributor, so may not be for the exact same models.

Bachman: Sold as "ready-to-run" units, these engines usually cost about $100 [$25 - $55 (RTR)]. The bodies are plastic. The running characteristics of these engines vary a lot. If possible, see it run before buying. Bowser (Cary Logo. Works) sells a conversion kit for these engines providing a new drive train, however this upgrade will cost nearly as much as the original engine.

MDC/Roundhouse: Sold as kits, these engines usually cost anywhere from $70 to $100 [$60 - $80 (kit)]. The boilers are metal, the cabs and tender are plastic. MDC makes smaller (and earlier-era) steam engines (4-4-2, 2-8-0, Shay, etc.).

Bowser: Sold as kits, these engines usually cost anywhere from $80 to $150 [$70 - $155 (kit), $120 - $170 (RTR)]. The kits are all metal -- very heavy. The casts usually require a fair amount of filing to remove any flash. Running characteristics are good and the pulling power is very good. Bowser provides a number of PRR steam era engines as well as a Challenger and a Big Boy.

Rivarossi: Formerly imported by AHM, these engines are sold "ready-to-run". They cost anywhere from $150 to $500 [$120 - $250 (RTR)]. The engines are all plastic. One or more of the drivers has a "traction tire" (rubber band) to keep the lighter weight engine from slipping. Running characteristics are good. Rivarrossi makes a wide variety of steam engines.

Mantua: They seem to offer two grades of equipment - the older designs such as the 0-4-0 switch engine which are quite inexpensive ($20) but which run poorly, and newer models such as the 4-4-0 Atlantic which seems like a very nice model for about $120. Some of the models come in kit form for less money.

Q. What companies make good equipment in G scale?

[The description of G-scale equipment was written by John Haskey]

In my opinion, Bachman track should be avoided like the plague. If you don't want to spend big bucks on LGB track, check out the REA track. REA makes very decent track and is usually cheaper than LGB. The Bachman track will do nothing but disappoint you.

On the other hand, the Bachman Locos and rolling stock are a very economical way to get into G-scale railroading. Their locos are noisier than their LGB counterparts but consider this: a Bachman 4-6-0 can be had for as little as $80 mail-order and it comes with lights, smoke, & sound. A similiar LGB loco will cost over $500. Granted, the LGB loco will probably last a lifetime but for someone getting started the Bachman loco represents a good value. Make sure you avoid the Bachman battery powered remote controlled locos though. I have friends who have been less than thrilled with them. Bachman's rolling stock is serviceable out of the box and, as others have mentioned, can be vastly improved by replacing the trucks and couplers. Their kits have great potential for kitbashing, etc.

I personally own both Bachman and LGB and don't regret purchasing either brand. If you're rich and have disposable income, by all means go out and get that LGB starter set, a few hundred feet of LGB track, and lots of cars and locos. On the other hand you could start with a loop of REA track, a MRC throttle, and a Bachman train and be well on your way as well.

Introduction to diesel locomotives

Q. I am trying to gain some very basic knowledge about diesel engines so that I can buy the models with some intelligence. Could someone give me the basic rundown of the different classes of diesel engines and what they were used for?

[This answer was edited from material written by Fred Ochs and later augmented by various readers]

A. Locomotive manufacturers

EMD: Electro-Motive Division of General Motors Before being bought by GM, it was EMC - Electro Motive Corporation.

GE: General Electric

Alco: Americal Locomotive Works

Baldwin: Baldwin Locomotive Works

Baldwin Locomotive Works was named after the "founding father" Mathias(?) Baldwin. In 1928 the Baldwin works moved from Philadelphia to nearby Eddystone, Pa. For a complete story of "the works", check the book _The Locomotives that Baldwin Built_ by Fred Westing pub. 1966 by Superior Publishing Co, Seattle Washington, also re-printed by Bonanza Books.

Lima: Lima-Hamilton BLH: Baldwin,Lima,Hamilton

The Lima and Hamilton plants were in towns of the same name in Ohio. These companies started out making steam locomotives.

(They never really succeeded in the transition to diesel, and even after merging eventually went out of business.)

MLW: Montreal Locomotive Works The successor to MLW was Bombardier who built some MLW designs for a while in Canada. The Montreal MLW/Bombardier plant is now run (owned?) by GE-Canada. Bombardier still manufactures railroad passenger cars in Barre, VT.

FM: Fairbanks-Morse

Also note that FM and Baldwin designs were built in Canada under license by CLC - Canadian Locomotive Company.

Only EMD and GE are still producing railroad locomotives.

A. A few naming conventions.

Diesel locomotives are designated by the number of powered axles, divided into trucks. The letters A,B,C,D stand for 1 through 4 axles, so an EMD FT (see below) with 2 trucks with two driving axles is a B-B. Early locomotives were made with A1A trucks (2 axles, the center one unpowered).

A units have a cab with controls for the engineer.

B units are basically A units with no controls.

Slugs are a cut-down frame filled with concrete. They have only traction motors, and receive power from an attached engine.

A. Names of locomotives

EMD's first main model was the FT, which stood for FourTeen hundred horsepower. (Commonly referred to as "the Diesel That Did It" since it was the first practical replacement for mainline steam power.)

It had 1350 HP(horse power) They were designed to be semi-permanently coupled and sold usually as sets. (Initially most railroads numbered them as one locomotive with unit designators such as A,B,C,D to get around union rules requiring a full crew for each locomotive.)

This was followed by the following engines:

F2A,F2B 1350HP

F3A,F3B,F7A,F7B,FP7 1500HP

F9A,F9B,FP9 1750 HP

The FP models were intended for passenger service, as they included a steam generator at the rear of an extended body. Passenger equipment was originally built to use steam for heating (since they were pulled by steam engines with a handy supply of it), so when diesels were introduced separate steam generators had to be added for passenger service. Modern equipment no longer uses steam heat, removing the need for extra equipment.

We also have the E unit, similar in appearance to the F unit, except it has A1A trucks. They also have 2 diesel engines in them, to give them more HP.

EA,EB,E1A,E1B,E2A,E2B 1800HP

E3A,E3B,E4A,E4B,E5A,E5B,E6A,E6B,E7A,E7B 2000HP

E8A,E8B 2250 HP E9A,E9B 2400 HP

Before making the F7, EMD introduced a new model type, called the BL1 It stood for Branch Line, had 1500 HP, and had the same motor that the F7 and GP7 (which I will explain) did. They followed this by the BL2, although it is argued what the change was. This engine had most of the cab style, with notches along each side, that would allow the engineer to see behind him better.

This was followed by the GP7 (and concurrently produced with the F7) The GP series stood for General Purpose, and had walkways along each hood. It camein both passenger and freight versions. Passenger versions had a steam generator in the short hood (typically called the nose) to heat the passenger cars. This engine had B trucks and 1500 HP here is a list of GP style engines:

GP7 1500 HP

GP9 1750 HP

GP15-1 1500 HP

GP18 1800 HP

GP20,GP28,GP38 2000 HP

GP30 2250 HP

GP39 2300 HP

GP35 2500 HP

GP40, GP40P(*) 3000 HP

GP40X 3500 HP

GP50 3500/3600 HP

GP60 3800 HP (current model)

The next frieght style is the SD series, which stands for Special Duty.

These have C trucks, instead of B trucks, and are typically a lot heavier

then their GP counter part. here is a list of their models:

SD7 1500 HP

SD9 1750 HP

SD18 1800 HP

SD24 2400 HP

SD28,SD38 2000 HP

SD35, SDP35(*) 2500 HP

SD39 2300 HP

SD40,SDP40(*) 3000 HP

SD45,SDP45(*) 3600 HP

SD45X 4200 HP

SD50 3500/3600 HP

SD60 3800 HP (current model)

SD70 4000 HP (newest model, in initial production)

Then there is the later F series, which was basically like the GP and SD, but had cowling over the engine, instead of walkways. This cowling is not part of the structural support, like the earlier F series. These engines include:

F40PH 3000 HP standard Amtrak engine everyone knows and loves :)

F45, FP45(*) 3600 HP

SD40F,SD50F and SD60F which are SD40,SD50/SD60's with cowling over them instead of walkways. Bought by Canadian RR's.

(*) Passenger versions, as indicated by extra 'P' in number

Now to the switchers, another long list! A switcher is typically, small, lightweight, and has a cab at one end, and no nose, instead it usually has large windows for visibility. EMD started out with the NC which had 900 HP, and was experimental. then followed with the following models:

SC,SW 600 HP

NC, NC1, NC2, NW, NW1, NW1A 900 HP

NW2,NW4 900 HP

SW1 600 HP

NW3,NW5 1000 HP

SW8 800 HP

SW600 600 HP

SW900 900 HP

SW7 700 HP

SW9,SW1200 1200 HP

SW1000,SW1001 1000 HP

SW1500, MP15 1500 HP (MP stands for Multi Purpose, still looks like a switcher though, and is the current production model)

The original names were derived as follows, although for example the SW900 is a 900 HP version of the original SW.

SC - Six hundred horsepower, Cast frame

SW - Six hundred horsepower, Welded frame

NC - Nine hundred horsepower, Cast frame

NW - Nine hundred horsepower, Welded frame

The other odd model EMD produced was the DD series, which had DD trucks. These were double ended diesels, and were roughly like 2 engines put together in one. They had the following:

DD35A,DD35B 5000 HP

DDA40X 6600 HP

Only Union Pacific had the DDA40X and the DD35A. Both UP and Southern Pacific had the DD35B

GE is a bit easier to describe. They started with the U series, which stood for Universal. They are either B or C, based on the type of trucks. All GE models use their HP in hundreds as part of the model designation, along with the type of trucks and the engine series. The U series had the following models:

U18B 1800 HP

U23B,U23C 2250 HP

U25B,U25C 2500 HP

U28B,U28C 2800 HP

U30B,U30C 3000 HP

U33B,U33C 3300 HP

U36B,U36C 3600 HP

There was also a U50 and U50C which was a double U25, with either 2 sets of B trucks on a span bolster (U50) or on C trucks (U50C) Sometime in the late 70's (1977 I think) they dropped the U series, and went to the -7 series, all models produced there after looked like this:

B23-7,C23-7 2300 HP

B30-7,C30-7 3000 HP

B36-7,C36-7 3600 HP

B32-8,C32-8 3200 HP

B36-8,C36-8 3600 HP

B38-8,C39-8 3900 HP (current model)

B40-8.C40-8 4000 HP (current model)

They have also flipped the designation to DASH-8 40B and DASH-8 40C

There is also a modification on the current production of engines, that being a cowl (like described before) or a safety cab. For EMD's the wide nose is designated by adding an M after the model name (like SD60M or GP60M) on GE is is a W, (Like CW40-8,DASH-8 40BW) They also have the full width cowl with a W (DASH 8-40CW) bought only by Canadian National and BC Rail (British Columbia Railway)

Most of this information is in the _Second Diesel Spotters Guide_ or _Diesel Spotters Update_

Q. How does a diesel locomotive work?

A. Actually, this is a trick question. Locomotives come in diesel-electric, diesel-hydraulic, and as a test a steam-electric engine was built. The first part of the name indicates how the power is generated and the second how it is transmitted to the driving wheels.

The diesel engines are huge internal combustion engines (sometimes more than one per locomotive), named after Rudolf Diesel who patented the concept in 1892. In a diesel-electric they are used to power electric generators, and the electricity is used to drive electric motors. These are called traction motors and one is attached by a gear system to each powered axle.

I don't know the details of how diesel-hydraulic engines work, but basically something like an automatic transmission is used to connect the diesel motors to the axles via driveshafts (I'm making this all up!) It turns out to be very difficult to build these to handle the large loads involved, so all modern locomotives [in the United States - see below] are of the diesel-electric variety.

Until 1980, there were still modern diesel-hydraulic locomotives built by the Deutsche Bundesbahn in West Germany (three major series: the good old two- motored 220/221 (V200), the light 211/212 with one motor and the cab in the middle and the 215/216/217/218/219 with one motor/two cabs for mixed service). Today there are no diesel locomotives built in Germany, because there are so many Russian or Bulgarian diesel-electric engines from the Deutsche Reichsbahn (East Germany). New diesel locomotives will be built in the diesel electric technology with 3-phased AC transmission.

Finally we have the steam-electric. I don't have the references in front of me, but I believe the New York Central experimented with an engine which looked like an F3 but which had a coal-powered steam boiler which as used to run a generator, with the rest of the system as in a diesel-electric. This is even more speculative than the diesel-hydraulic description, so don't bet any money on it.

Q. What are "dynamic" brakes

A. As described in the previous question, diesel-electric locomotives have motors attached to each axle. Normally power is supplied to the motors causing the wheels to pull the train. However, due to the magic of electromagnetics, if the wheels are turned by an external force (such as gravity pulling a train down a hill) the motors will run as dynamos, generating electricity. Since energy is conserved, this electric power has to come from somewhere, which in this case is the kinetic energy of the engine. In simple English, running the motors as dynamos will put a drag on the engine, which can be helpful when running a very heavy train down a long grade.

The amount of electric power generated is substantial, and it has to be used up somehow to cause a drag on the wheels. This is done by using a bank of resistors which convert the electricity to heat which is then radiated away. On EMD locos these resistors appear as a bulging grille near the center of the roof. Alco, GE, FM, and BLW locos with dynamics have extra grills somewhere on the loco, but no bulges like the EMD "blister". On older Alcos (like RS3's) and on the Baldwin DRS/AS types, these grills were in the short hoods.

Model shells are often offered with these external indications of dynamic brakes, although they of course have no function. A given prototype locomotive is usually available both with and without dynamic brakes.

Q. How do steam locomotives work?

A. Steam engines came in three basic varieties: reciprocating pistons, geared drives, and experimental turbines. All work by boiling water to make pressurized steam, and the energy in this steam is used to move the engine. The earliest engines burned wood for fuel. Most steam engines used coal, and towards the end of the steam era oil was used, primarily to get around air pollution regulations.

In a reciprocating piston design the pressurized steam is sent into expansion cylinders, which were usually mounted on the outside front end of the frame. The steam expands to push a piston back, and the piston is connected via a crosshead to the main driving rods. These rods convert the linear motion of the piston to the circular motion of the driving wheels. There are many variations on this design, such as using multiple cylinders to increase the amount of energy extracted from the steam but they all fall into the category of improvements to the basic design. Note that once the steam has been used it is exhausted to the atmosphere, which is why the tender on a steam locomotive is mostly water and a relatively minor amount of fuel. Note that this design with lots of exposed moving parts is also significantly sexier than a diesel electric...

I have no idea how geared locomotives work -

As a PRR fan I will attempt to describe their turbine engines - other experiments may have differed in the details. As before steam is produced, but rather than using pistons is was fed through a rotating turbine which was directly geared to the driving wheels. Apparently the design did a fairly good job of producing power efficiently, but the steam had minute particles of coal ash in it which rapidly destroyed the finely balanced turbine blades, making it impractical to maintain. GE also produced such an engine, with the same problems.

Q. What is a "gas-turbine" locomotive?

A. General Electric produced several species of gas-turbines, as did Baldwin. These locos were basically the same as a diesel-electric, except that the prime mover was a gas turbine. The only successful production models came from GE, all of which were sold to the Union Pacific. These came in essentially two types:

- The first version was a 4,500 h.p. model introduced in 1949. The prime mover was a GE gas-turbine which turned a generator to provide current to eight traction motors. Wheel arrangement was B-B + B-B, the same as the later U50.

- The second model went into production in 1958. It consisted of two car bodies, a lead control unit and a second unit containing a 10,500 h.p. GE gas-turbine. Each car body had two C trucks. At first, the two generators attached to the turbine were rated together at 8,500 h.p., later uprated to 10,000 h.p.

Thirty large turbines were produced by GE. Compared to first generation diesels, these machines were reliable. They consumed huge amounts of "Bunker C," a thick black oil which was considered waste at the time and was initially very cheap. Heated tenders [to keep the fuel from solidifying] were provided for each locomotive, custom made from old steam tenders. Bunker C became more expensive when it became an ingredient for making plastics. Increased fuel expense doomed the gas-turbine, which could not operate with the fuel efficiency of the diesel. [No way was ever found to cool the turbine blades like a piston engine cooling system so the turbine had to operate at a lower less efficient temperature than a diesel.]

Gas-turbines were in revenue service roughly from 1950 to 1969. None of the first generation turbines remain. At least one of the second generation turbines is on display (in Ogden, Utah).

Gas-turbines have also been used in Europe. The SNCF (French National Railway Society) introduced its Turbotrains ETG (Element a Turbine a Gaz) and RTG (Rame a Turbine a Gaz), very noisy passenger units of four to five wagons, in the sixties. They can reach 180 km/h and are still in use as fast trains on the non-electrificated lines today. A variant of the RTG is in use in Canada. The other European companies have stopped their tests with gas turbine traction, because gas turbines consume large amounts of fuel and produce a very loud high frequency noise.


Q. Nickel-silver vs. brass: what are the issues?

Nickel-silver is a copper-nickel alloy (mostly copper), considered to be metalurgically similar to brass but superior in corrosion resistance. Brass oxidizes rapidly to a non-conducting surface, which means that power will not reach the locomotives or cars, resulting in stalls. Both forms of track will accumulate other gunk on them, requiring some form of cleaning. In general, nickel silver is much better than brass, and is worth the small extra cost.

The more recently developed alloys used in high-quality G scale track are much less corrosion-prone. Brass is sometimes favored over nickel-silver for outdoor use, because it expands and contracts somewhat less with changes in temperature.

Q. What does the number associated with a turnout mean? What's the difference between, say, a #4 turnout and a #6 turnout?

The number is based on the angle between the straight and diverging tracks. Skipping the exact definition, a #4 turnout is generally the sharpest practical size and is equivalent to an 18" curve. #6s and #8s are more gradual and are typically used on larger layouts both because they look more realistic and because longer equipment will work better on them.

Traction models and models in the smallest scales (N and Z) can often get good results with much smaller turnout numbers, down to #2.5 in common usage.

Q. What does the "code" associated with track mean?

This is the height of the rail, expressed in thousandths of an inch. Code 100 rail (common in HO) is 0.100 inches high. This is equivalent to prototype rail weighing 152 pounds per yard, which is larger than almost all rail used by real railroads in the United States. Advanced modelers typically use rail sizes closer to that used on the prototype, as shown below:

Nominal | Mass | Scale | Scale | Scale |

Scale | Market | Mainline | Branch | Mining |

G, #1 | .330 | .250 | .175 | .125 |

O | .175 | .148 | .125 | .100 |

S | .148 | .125 | .100 | .086 |

HO/OO | .100 | .083 | .070 | .055 |

N | .080 | .055 | .040 | n/a |

Z | .062 | n/a | n/a | n/a |

Q. When handlaying track, how/when do you folks glue down the ballast?

Ballast is added in the same fashion for both handlaid and prefabricated track. The roadbed is prepared and the track laid in position using your favorite method before any ballast is added. The method described below also works just as well for grass, dirt, etc. in the rest of the layout.

There are several methods, but the basic idea is to spread the ballast in place (I use a cheap 1" paintbrush to shape it), soak it with some sort of wetting agent, and then flow a fixative into it. Variants abound - this is a FAQ in the model railroading magazines as well, so look there for alternatives.

The most common wetting agent is tap water with a drop or two of standard dishwashing liquid added to cut the surface tension (the water will just bead up otherwise and won't soak the ballast). This can be sprayed on with a *fine* mister or carefully dripped on with an eye dropper. The most common fixative is a 50-50 mixture of white glue and water, again with a drop of detergent. This is dripped onto the ballast and allowed to dry. All of the water will evaporate, so the ballast should be as wet as possible without floating it away; otherwise you may just glue down a top crust which will chip away later.

Q. Also, who makes good ballast material, and do you mix/combine several coarsenesses or make it uniform?

Woodland Scenics is probably the most popular brand, but at least one poster described it as looking like kitty litter; a bit harsh but not far from the mark in my opinion. Their finest grade should be used by N and HO scales, and it's really too coarse for N.

The other major source is actual rock. You can just walk outside if you live in the area you model, you can try the local quarry or gravel operation to see if you can get a small sample, or you can order it from several operations which advertise in the model railroading magazines. If you use real rock you must crush it, sift it to size, and then remove any ferrous particles with a magnet.

Note that most real railroads use ballast that is available locally, so the color of your ballast will differ based on the area modelled. Most of it is a standard gray, but iron ore roads have a distinct reddish hue, and RMC just finished a series about a marble quarrying railroad which used marble chips!


[The following description of Homasote was written by Gregg Fuhriman]

My Experiences

Homasote is a material made of densely compressed newsprint, and is usually sold in 4' x 8' x 1/2" sheets. It is also available to the model railroad hobby as precut roadbed strips. My experience is with the large sheets, which I purchased from a building supply store. In 1987, one sheet cost around 25 dollars.

I cut it into many 8' strips, using a rotary saw set at 45 degree angle to get the "ballast slope". The ascii drawing below shows an edge-on view of how I cut the Homasote sheets:

||<---- wide enough for track


|\ / \ / \ / \ / \ / \ / \ / \|


<---------- 4' ---------->

These strips were then used as-is for straight roadbed. To make curves, I cut dozens of kerfs crossways about 3/4 of the way through the strip and about 1/2" apart. The strip could then be "bent" into the desired curvature by compressing the kerfs on the inside of the curve. The purpose of this exercise was to reduce wasted Homasote; it is not a cheap material.

The homasote strips were then glued to plywood sub-roadbed using carpenter's glue and clamps. I also drove small nails through the Homasote into the plywood to help hold things in the right position while the glue dried. Special shapes, like around switch stands, were shaped by hand using a utility knife to carve the homasote.

Summary of My Experience and Netter's Comments

Benefits of Homasote are that it holds spikes and nails well, and it is a sound-deadening material to reduce train noise. It glues easily, as it is a porous material. It is relatively "soft", so it cuts easily.

Cutting this material with a power saw generated piles of fluffy, gray dust that went everywhere and proved to be a pain to clean up. I reccommend wearing a dust filter to avoid breathing in the dust and fluff. Cutting with a utility knife is neater, but more difficult and tedious as the homosote tends to "grab" the blade (just as it "grabs" spikes and nails).

Forming curves with the kerf-and-bend method was not 100% successful. At least half the time the strip would break in two. Also, the resulting curve is not super smooth ... they are actually several short straight sections. Heavy sanding can smooth out some of this (but with more dust).

Other netters have suggested painting the Homasote with a latex paint to help seal it against moisture (introduced mostly during ballasting, but also to guard against ambient humidity). Its dimensional stability with respect to temperature and humidity has been panned, though I have not noticed problems with my layout so far.

Layout planning software

Q. Could someone please give me the name of the Abracadabra product that is like "flight simulator for trains", i.e., the one that lets you simulate being the engineer on a layout you program into it. There are several products on the market with similar sounding names and when I call around to try and find it at one of the local software houses I want to make sure that I'm asking for the correct one.

"Design Your Own Train" and "Run Your Own Train" are a pair of programs that let you do what you say. RYOT gives you a "hogger's eye view" of the road; that is, the view is supposedly that which you would see from the cab.

"Design Your Own Railroad" allows you to create a layout complete with scenery, then run trains on the tracks. You only get a bird's eye view, though.

I personally have used DYORR, and recommend it. I have not used DYOT or RYOT, but have heard that they are less sophisticated products. Of course, if you are determined to have the flightsim-style view out the windshield, RYOT is your only choice.

All three products are published by Abracadata software, (800) 451-4871. It's cheaper to order the products from MicroWarehouse, however: (800) 367-7080.

[Editor's note: I've also seen advertisements for products which look more like CAD packages tailored to model railroading. I have used XTrkCad and RightTrack software, and they both work well for desigining a scale model railroad.]


While we don't have much on this subject yet, Model Railroader manages to get a monthly column plus additional articles out of it each month so there must be something to talk about. As always, feel free to send in stories about how to paint, what color to paint it, etc.

Q. How do I paint this $1,200 brass model I just purchased?

Well, being handy with an airbrush is the "only" place to start playing with brass... if you don't already have some experience... practice airbrushing on some less-expensive (and less detailed) stuff.

My [Dennis Lippert] "system" for painting brass steam locos has always been basically the following:

(1) Test-run the loco... to make sure it ran before you took it apart(!). Check all of the valve gear and rods for loose screws, tighening if found. It might even be a good idea to fully break-in the loco before putting it through the "trauma" of disassembly. (2) Disassmble as follows: remove lead & trailing trucks. Detach the boiler from the frame. Install the weight (if it was just wrapped up and sittiing in the box). Remove the trucks and couplers from the tender, and remove its body from the frame also. If the smokebox front is removeable, you might want to take it off also. This *should* be all the disassembly that will be necessary. (3) Inspect the model. Fix anything broken, and check out the factory clear-coat lacquer. If the lacquer seems to be smooth and isn't chipping off, use it as a primer for your paint. If the lacquer is no good, strip the loco (I use ScaleCoat's stripper). (4) Wash the loco with soap and "water as hot as you can stand". This is to make the surface clean so the paint will stick better. Don't worry about getting the motor/drive wet. As long as it dries completely before putting power to it, it will be OK. Let the model dry for at least a few hours, preferably overnight. After washing the parts, always wash your hands before touching the model (or better yet, wear rubber gloves). (5) If the loco was stripped, it needs to be primed. I use a PPG two-part epoxy primer (because a friend got it for me), code-named DP400/DP401. You mix equal parts of the two bottles, let sit for 30 minutes, then thin with lacquer thinner and spray (it will only last a couple weeks in the bottle after being mixed, so don't mix much). It should be noted that Floquil's "primers" are basically just paint colors with thicker pigment (for sanding). They DO NOT adhere to the surface any better than the normal paints (this from a PPG paint chemist who has "chemically dissected" them). (6) Prepare your paint. I like Scalecoat II because of it's good coverage and shiny surface. You get the best smoothness if the paint is slightly on the thin side, rather than slightly thick. But just *slightly*. (if Scalecoat is overthinned, it will chemically "fall apart". (7) Adjust the airbrush to spray a very small amount of paint. Our first area of attack will be the chassis. Connect power leads to the frame and the drawbar, and put about half-power to the chassis. Hold it by the motor (assuming can motor), and spray all of the stuff that's moving, from various angles. sit the chassis aside, upside down, and leave it running for five to ten minutes (to make sure the paint doesn't stick anything together when it dries.) Since the airbrush is turned down right now, we can also spray the lead truck, trailing truck, tender trucks, etc. Be sure to hit them from many angles, and to roll them around while painting them. ( A skill in itself... hitting a moving target! :-) Possibly the single biggest trick in airbrushing brass is getting paint on everything that will be seen (a bare spot under a detail on a black plastic loco looks like a shadow... on brass it looks like someone forgot to paint it!) (8) open the airbrush up to a "normal" spray pattern. Start to spray any part (boiler, tender, etc.) Begin by spraying from obscure angles around all details. Then come back and lay a smooth overcoat over the entire area. (9) once done with the main body parts, you can come back to the chassis. Spray all non-moving parts with the "heavier" spray pattern. Try to avoid spraying on the moving parts (since they're already painted). Again, the motor is the nicest handle to hold with. (10) Now you should notice that everything is painted (unless I missed something). In the case of a PRR steamer, the boiler and tender body should be brunswick green, the chassis components should all be black. Take some time to look at all the parts from any angle that you can... there WILL be bare spots somewhere (trust me!) (11) Wait for things to dry. With Scalecoat I paint, this can take days to quit being tacky. Suggestions to speed drying include: -put it outside if it's a nice warm sunny day... in the sun. -put it in front of a forced-air furnace (warm, dry air is good) -bake it (I've never "baked" - don't look to me for suggestions The best idea is to do one of the above to remove the tackyness, and still let the parts sit for a week. This guarantees that everything is dry and hard. (12) prepare for next color(s). On most steamers this would include graphite smokeboxes, Oxide red tender decks/cab roofs, etc. Check your prototype! Mask carefully, but prepare yourself for the fact that you *will* get overspray under the masking. Luckily, black is easy to touch up. Always "overdo it" with metallic colors, and cover up the overspray later. The metallics are incredibly hard to touch up without it showing, so make sure everything that is to be metallic gets sprayed the first time. (13) Apply next color(s). Using a very low pressure (10-15 psi) to keep overspray to a minimum. Remove masking as soon as you are done. "Bake" again. [You can often do two or more "extra" colors at one sitting... as long as they aren't too close to each other on the model (overspray problems).] (14) Clean paint from parts which must make electrical contact. These include tender truck bolsters, wheel treads, drawbar, etc. with lacquer thinner and Q-Tips. The engine drive wheels are easiest to clean if you again run the chassis on a power pack. (13) Reassemble the loco. After reassembly, do any kind of touch-up work and details. (i.e. if you did a graphite smokebox, the railings, etc. will also be graphite, so repaint them [black]). (14) Dullcote the loco (or semi-gloss) after decaling. This will seal the decals and give "an extra layer of protection" against chips. (15) Weather the loco if you like, wrap it up, take it to the club, and begin to brag. This is the most important step, as very few people seem to realize that it takes more real effort to read this message than it does to get a good paint job on a brass model! Above all, follow these simple rules: - have fun... painting your first couple of brass locos can be stressful. - take your time... it's not that important to get done today (or even this week!). - use a spray booth, rubber gloves, and possibly a respirator. A simple mask won't help much... as the pigment is the least of your worries. These may seem like overkill, but we are looking at a couple of hours at the booth... much more time than, say, painting a freight car.


Q. What are Kadee couplers and why should I use them?

Most locomotives and rolling stock come with an industry-standard coupler - for HO they are X2f (commonly called horn-hook) and for N they are Rapido. These couplers are only suitable for those who don't plan to do much switching and coupling/uncoupling of the cars, their primary advantages being that they are free and require virtually no adjustment.

Kadee makes a line of more prototypical looking couplers that are available in all common scales and which are used by most serious modelers. They are magnetically operated, allowing you to uncouple cars without touching them. Uncoupling ramps made of permanent magnets or electromagnets can be positioned at strategic places on your layout to perform this uncoupling. Rix (another company) sells an inexpensive magnetic rod which can be held between the cars to uncouple them without removing them from the tracks. Note that Kadee couplers are not compatible with the standard couplers, so once you switch you'll have to convert all of your equipment. In HO the most common size (#5) costs $2.95 for a package of 4 (2 cars).


Portions, no ALL, of this file have been contributed by the following people: (David G. Baird) (Steven Bellovin) (Doctor Blues) (Bruce Burden) (Ben Dibble) (David Emery)
zehntel! (Gregg Fuhriman) (Bill Gripp) (John Haskey) (Andre' Hut)
msjohnso@donald.WichitaKS.NCR.COM (Mark Johnson) (Mark Johnson) (Van Kelly) (Tim Kirby) (Tobias B. K'ohler) (Greg Lewis) (Jean-Pol Matheys) (Fred Ochs) (Matt Pedersen) (George Robbins) (Joe Russ) 
js@hplvec.LVLD.HP.COM (Jon Sawyer)
romeo@niagara.Tymnet.COM (Michael Stimac) (Ralph Marshall)

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