Although it can often be hard to tell at a glance, tank cars are among the most specialized cars on the rails. There are many modifications that can be added to the basic tank to make it suitable for specific commodities.
One of the more common variations is the addition of heating coils. The viscosity of some loads increases as the temperature drops. This does not pose a great problem in transit, but it can make the car difficult to unload. To speed the process, the load must be reheated.
Heating coils like the ones shown here are not kept hot for the entire trip, but can be charged with steam at the unloading site. Steam is supplied by a stationary boiler connected by piping to a input valve on the tank car. After warming for a few hours, the car can be unloaded without trouble. These coils are normally conceiled within an outer skin and can’t be seen normally. One interesting adaptation to this practice can be occassionally seen on the Strasburg Railroad which has been known to tap the boiler of one of their steam locomotives to warm cars for customers in the colder months!
The car seen here is actually a special training car. It is used to train railroad employees and local fire departments on all of the things they may encounter on a tank car, either through their normal work or in the event of an emergency. This first-hand training can be invaluable in the event of a derailment. In addition to this heating coil demonstration on the side, the car features a row of different hatch and vent styles along the top, unloading valves underneath and doors on the ends for access to more exhibits inside.
Previously owned by Union Pacific, this car was found with these new modifications at the Union Tank Car facility in Altoona, PA (in the old Pennsylvania Railroad passenger car shops). The car now wears MCVX reporting marks, which belong to the Massechusettes Volunteer Fire Company. This group owns several tank cars which tour the country to provide this training. Other large chemical and tank car companies own similiar cars of their own.
Modeling heated tank car operations doesn’t normally require anything special. An extra pipe at the unloading site is normally all you’d see. Ambitious modelers could hide a smoke unit between the rails there as well to recreate the escaping steam. Of course a training car could also make an interesting scene, set on a siding and surrounded by fire trucks and fire fighters gathered around for their lessons.