When large and heavy loads need to be moved long distances railroads are often the best choice for the job. These loads are often tall enough that they wouldn't pass safely under bridges or other obstacles if carried on conventional flat cars. To provide extra clearance, railroads use heavy-duty, depressed center flat cars. The lower center deck provides several inches of extra clearance, and since the cargo does not have to be lifted as high, loading and unloading is easier. Weight is also a factor, so load limits (combined weight of the car and cargo) approach 200 tons. The car itself is made of high-strength, low-alloy steels to conserve weight, which is spread over numerous support members. The most visible are the two high-capacity, four-axle trucks at the ends of the car. Each pair is connected by a span bolster, which pivots on the bolster located on the car body. This spreads the weight over eight axles to help prevent overloading. With almost no room below the car, separate air and handbrakes for each pair of trucks are carried on platforms at the ends. Fully assembled and ready for service, this HO model features a diecast metal body for outstanding performance. One of the most common loads for cars of this type are large electrical transformers, which can be modeled using the Cornerstone Series(R) Transformer kit (#933-3126), sold separately.