The Trainz SKU for this item is P12269051

While they're shown as a specific scale

Unit Measures:11 5/8 x 2 5/8 x 3 3/4 and Operates On O-31 Curves

Model Number: 6-84855

such as piping and walkways

Athearn 23438 N Union Pacific ACF 2970 Covered Hopper #219755 ProductID_11397217 The Trainz SKU for thisThis is an Athearn 23438 N Scale Union Pacific ACF 2970 Covered Hopper #219755. Features: Round or trough hatches, Photo etched metal roof walk, Separately applied wire grab irons and stirrup steps, Detailed outlets, Fully assembled and ready to run out of the box, Accurately painted and printed, Highly detailed, injection molded body, Screw mounted trucks, Highly detailed, injection molded body. Separate brake wheel, cylinder, valve and air reservoir