The word “extreme” today is often used as a catchphrase for anything even slightly better than average. Not so here with these flatcars. Some of the specially designed cars on today’s railroads are unbelievably big and complex. They may in fact be too big for words. But if not, we’ll settle for “extreme!”
What sets these cars apart from the rest? For one thing, capacity. Some of the cars seen here may carry loads approaching one million pounds in weight. Think of a Pennsylvania Railroad M1. Now picture a car strong enough to carry two of them with nearly 100 tons of capacity to spare. By any standard, that is impressive.
Although they still have a flat deck to carry the load, these cars share little else in common with a traditional flatcar. In fact, the light weight alone of some of these large cars is greater than the capacity of many standard freight cars. Supporting all of that weight requires a lot of wheels, bolsters and engineering.
For the ultimate in flatcar technology, consider KWUX 200 built in 2013 by Kasgro Rail in New Castle, Pennsylvania. Not only can the car support a 477.5 ton payload, it is equipped with hydraulic pistons which can raise the car deck up to an additional 24 inches and move it 14 inches side-to-side to help clear obstacles along the right-of-way! This can be a huge help when navigating curves. A load this large can make even the prototype’s curvature feel like O-27.
Although this car appears to have a “depressed center” design. Thanks to the thickness of the 40 foot deck, the load is still higher above the rail than most conventional cars. The tall towers on either side help sling the weight onto the sets of trucks while keeping the center of gravity as low as possible. The trucks themselves are connected in pairs with special span bolsters. These bolsters are then connected to each other and finally to the sloping supports for the flatcar deck. This articulation gives the car both the necessary weight distribution and agility to navigate curves.
What Do They Carry?
The largest of these cars are designed for heavy power assemblies including transformers and turbines. The largest cars may make only a few trips a year – or less – but they are the only practical way to transport these loads. And a single trip or two may cover the cost of the car’s construction.
The Department of Defense is another large user of heavy-duty flatcars including both depressed-center and straight deck designs. These can be used for a variety of special loads from heavy machinery to radioactive material casks.
With their infrequent use many of these cars can stay in service for decades. The cars are also frequently modified, particularly the decks, to safely secure each unique load. It is not uncommon for newer cars to reuse rebuilt trucks from earlier heavy flatcars as well.
Even when empty, these large cars often require special handling. If handled in general freight they are usually placed at the very front or rear of the consist. Loaded cars however can often require a train of their own. Not only are they big and heavy, these loads must often travel at very reduced speed and stay clear of other traffic on the line.
In a dedicated train, it is not uncommon to see empty idler cars placed between the heavy flatcar and locomotives for added protection on bridges. Flatcars and gondolas are most common so that the crew will still have an unobstructed view back to the load.
Cabooses are also still common as a rider car to accompany these special moves. The railroad may provide the caboose (or an extra caboose in the days when there was still a train crew to accommodate at the rear of the train.) Today, the rider caboose is often supplied by the same company as the flatcar. the two cars will stay together – even on the empty return trip.