The 5660 Pressure Differential (PD) Covered Hopper was introduced in 1999 by Thrall Industries, as the most advanced design in the evolution of Pressure Differential Covered Hopper, a special breed within the covered hopper family. Production still continues today under the TrinityRail brand, following Trinity’s purchase of Thrall, with nearly 4,000 examples already built.
![TRINITY 5660 PD COVERED HOPPER GE RAIL SERVICES [NAHX] #60762 TRINITY 5660 PD COVERED HOPPER GE RAIL SERVICES [NAHX] #60762](https://d2j6dbq0eux0bg.cloudfront.net/images/101064502/5306781663.jpg)
