In 1995, Trinity Industries introduced a new center-sill design covered hopper car designed primarily for grain transport. The new design was visually quite different - this one featured curved sides versus previously familiar rib-sided design adopted from Pullman-Standard. The new 5161 cubic-foot capacity design along with the recently introduced allowable 286,000 lbs GRL (Gross Rail Loading) brought a new standard to the industry (Trinity's competition were ACF and Thrall).
Initial deliveries went to Trinity's leasing component and to ADM Transportation, a large private company heavily invested in grain products. Within months, deliveries to the other "grain" companies began rolling down the steel rails. Eventually, the traditional grain railroads jumped in on the game with BNSF leading the pack. The 5161 grain variants have long trough hatches usually broken into sections for easy opening. The outlets on grain cars are usually gravity-only and vary by manufacturer. Fixed shaker brackets can be found on the hopper sides.
Here's what ExactRail has to say about these -
ExactRail proudly anounces the release of our new N Scale Trinty 5161 covered grain hoppers. The hoppers are avalable in 8 assorted road names available in 3-packs. Most roads have 9 road numbers (3 in each 3-pack). This car is a must-have for the modern modeler who loves unit grain trains and is a great addition for anyone who appreciates a highly detailed model worthy of their layout.