Derailments

Staying on track

Written by Tom Bee

I think the number one issue for railroad safety today is track condition. Track can deteriorate slowly over time so it's an often over looked item.  Aluminum rail will wear out in time. Worn out rail must be replaced.  Ties, wooden at least, will rot with the seasons. Make sure all your ties are secure and in good shape. Maintaining a level track is very important.  It must be level, even in curves.

Some scale railroads will try to raise the outside track slightly like a race car track that has "banked turns". We don't need superelevation in live steam railroading.  Superelevation is meant for high speed trains. Running our trains at a high enough speed for superelevation to help would mean you are running way too fast.  High speed trains are dangerous. I believe top speeds for 7.5" gauge railroads should be 5 mph. at the most.

Improper wheel profiles can lead to track and switch damage. Wheel flanges must be rounded.  The above drawing gives my suggested dimensions for a 7.5" gauge wheel profile based on IBLS standards. 

Track safety would also include the proper design of switches and all crossovers. To eliminate derailments, you must also be concerned with train car design. I cannot stress enough about the importance of frame design. These frames must be made flat.  A twist in the frame is the same as a twist in the track.  And a twist in the track can and will derail a car. Take a close look at a real track when a train goes by.  The track dips down with every wheel set. It dips a distance of the flange height. This makes it almost impossible to derail. Our track does not dip.  It's too ridged. So that's why we need it to be as flat and level as possible.

You need to maintain flexibility in your trucks. How much flexibility should you have in your trucks? Flexibility in each truck is important because there is no such thing as a perfectly flat track. You want each wheel to be able lift at least 1/4" because of sticks and stones that sometimes make their way under the wheel. Another very important flexibility should be in the bolster. Each bolster should flex from a level frame about 10 degrees. What this does is, allows the car to stay on a twisted track. Some people put washers between the bolster and the frame to give the bolster more than 10 degrees of movement. This is fine for rolling stock and cabooses, but not for "people hauling" cars. It's just too unstable for people to ride. I have rode on cars that tip more than 10 degrees and it's not a nice ride. And besides that, tipping too much changes the center of gravity to one side. When the center of gravity is moved to one side too much, you will get rollover. The perfect riding car would be one that has flex in itself. Build a riding car that the entire body twists and keep the bolsters wobble free, and you will have a nice, safe riding car.

Why is setting up the springs important and how do I know I have the proper amount of "spring"? The proper spring is very important because the springs help the car to have flexibility. You want the springs to be compressed a little, even when empty. I carry four different spring weights. they are all the same length. Which means you can mix and match them if you like. If our model cars were real heavy, say 1000 pounds empty, then we wouldn't have to worry so much, because the load would be much lighter. A heavy car holds the track much better. This is a major problem in our hobby. The loads are always heaver than the car. It should be the other way around.

There are other safety items like chains and drawbars are good but, they are good for after the car has derailed.  Lets do something to prevent the car from derailing in the first place.