MODEL RAILROADING with   LAURIE GREEN

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KEEPING THEM ON TRACK

Probably the most frustrating and annoying aspect in our hobby of model railroading is when our locomotives and rolling stock continually derail. This can occur not only on hand laid track but also on commercial track, and this problem is the main reason why the hobby loses many modelers. However this need not be the case. By following a simple check list, most of the derailment problems and poor running qualities can be eliminated, or at least minimized.

This check list can be divided into three distinct sections:

1. LOCOMOTIVES AND ROLLING STOCK

2. THE ROADBED

3. THE TRACK WORK

Several tools are required to perform the following checks on your track and rolling stock:

WHEEL AND TRACK GAUGE  

( an NMRA gauge is recommended )

SHEET OF GLASS

( 6mm thick by about 300mm x 100mm will do )

STEEL RULER  

( your 300mm scale ruler will do )

SMALL SET SQUARE

( about 50mm x 100mm )


SECTION ONE: LOCOMOTIVES & ROLLING STOCK

These checks should be performed on all your pieces of rolling stock when they are bought or built and should be done whenever a piece of rolling stock gives you trouble.

WHEEL GAUGE - using the track gauge, check that all wheel sets are correctly in gauge.

AXLES - check that both axles are parallel to each other and also parallel to the cross centre line of the bogie.

WHEEL POSITION - place the steel ruler against the flanges on the two wheels on the same side of the bogie, ensuring that the bogie is in line with the centre of the car. The ruler should be parallel with the centre of the car. If this is the case the bogie will track correctly.

LEVEL WHEELS - place the locomotive or piece of rolling stock on the sheet of flat glass. Check that every wheel touches the glass when the wheels are straight as well as when they are fully turned in both directions.

WHEELS - check each axle will spin freely. If not, check the axle ends and the journal boxes.

BOGIES - ensure that bogies will rotate smoothly and that they remain level when rotated.

CURVES - place the locomotive or car on some track of the minimum radius that you will use on your layout and check they will run smoothly on that curve.

COUPLERS - make sure that each coupler is free moving in its housing and has enough sideways movement not to cause cars to derail on your minimum radius curves. If the coupler does not have enough sideways movement they will lift the wheels on the outside rail and can cause the cars to topple to the inside of the curve.

WEIGHT - weight each car to ensure they are heavy enough. The NMRA has a set of specifications available.

WHEEL GUNK - with dirty track, oil and dust, gunk can build up on wheel flange areas causing rough running.

SECTION TWO - THE ROADBED

Just like the prototype, good track starts from the sub-roadbed up. A model roadbed should be solid enough to stop any warping, contraction, expansion, or bludging. All these things will distort the track we lay on top of this roadbed, causing many problems that are hard to locate and remedy.

MOISTURE - This is the biggest cause of problems occurring with the roadbed. Using materials that will not absorb moisture or by sealing the material will hopefully solve this. I have found a wood frame with 50 mm medium density white polystyrene foam and 6 mm thick MDF ( Medium Density Fiber Board) roadbed works well. These are all "Liquid Nailed" together to form a very stable base. 'Liquid Nails' marketed by Selleys and is a construction adhesive available in cartridges at all hardware and building suppliers.

UNDULATIONS - By placing the steel ruler along the centre line of the proposed location of the track you can see if there are any severe undulations in the roadbed. These will have to be eliminated before any track is laid.

YAWL - Place the small set square across the roadbed and check that the other edge is vertical, then move the set square along about 100mm and check again - a second square is handy here so you can site against the other. Two business cards can also be used. The square should still be vertical. Continue to check along the roadbed. If the edge of the square doesn't remain the same along the roadbed, you get a yawl effect, similar to the movement of a yacht moving on a gentle swell, and this movement, if severe enough, will cause derailments.

TRANSITIONS - Where level roadbed and a grade meet, ensure there is a smooth transition between the two.

SECTION THREE - THE TRACK WORK

This section is primarily aimed at hand laid track, however most of the checks also apply to commercial track work. Smooth running hand laid track work has to be as close as possible to perfect. But don't be deterred, if you use the following check list, gain some practice and draw on your patience you will get excellent results.

TIES - Once the ties are laid on the roadbed, place the steel ruler along the ties where the rail will be laid and check that all the ties are level. Sand any high ties to the correct height and raise any low ties until the tops of the ties are level.

GAUGE - It is most important to have your track in the correct gauge. I recommend the NMRA track gauge, as you can check your wheels, track and turnouts with the one gauge and know that the are all compatible. This gauge comes with a complete set of instructions on all the uses and checks that should be made on track work.

CURVES - When checking straight or near straight track I gauge the track exactly to the NMRA gauge, how ever when I am laying curve track, especially track that is close to the minimum curvature, I increase the gauge to the

maximum of the gauge (one side of the gauge will drops of the shoulder) - this increases the track gauge by about 5

thou of an inch. Increasing the gauge on the minimum radius curves allows the locomotives and rolling stock to move

through the curve freely. If the gauge is to tight, the wheels on the outside of the curve tend to lift and then derail.

TURNOUTS (LEAD AREA) - Make sure that the blades seat snugly against the running rail so the wheels will pass along the chosen route and not pick the wrong route. With STUB turnouts, ensure that the move able running rails line up perfectly with the fixed rails of the turnout, and ensure the tops of all the rails are the same.

TURNOUTS (FROG AREA) - It is critical that the rails passing through the frog area are exactly in line, and that the wing and check rails are positioned correctly and at the proper spacing and gauge. This is where the NMRA track gauge is invaluable. Follow the instructions that come with the gauge and this will eliminate most of the problems in this area.

FROG - Ensure that wheels do not drop into the frog as they pass over it.

YAWL - As you did with the roadbed, use the small square and by laying it across the track about every 100mm check that the track does not have any dips or rises in one or both rails.

SPIKES AND BALLAST - Be sure that all spikes are firmly down and below the bottom of the wheel flanges. Also clean away any ballast which the wheel flanges may hit.

EXPANSION GAPS - When laying rail, leave a small gap between the rails to allow for rail expansion. A thick

business card placed between the ends of the rails is a good gap size.   

COMMERCIAL TRACK  - When laying flexible track do not hammer the track pins in too hard as this  will push  the middle of the tie down and at the same time distort the rails up, closing the gauge and causing a hump in the track.  

CONCLUSION

While there might seem like a lot of things to remember  when checking your locomotives, rolling stock and track work, most of the points will become habit and you will do them automatically. The important thing is to ensure that you start these habits from the baseboard up and remember that you might not get it right first time, but with perseverance, you will have years of pleasure in the hobby.