The National Model Railroad Association (NMRA) has Standards and Recommended Practices for various things for Model Railroads. These range from track spacing, wheel profiles, module specifications, and Car Weight. I’m going to focus on Car Weight for a little bit.
RP-20.1 Car Weight sets up a recommended practice for what the model cars should weigh. It rather straight forward, start with 5 ounces and add 1 ounce per inch of car length.
I’m going to add different models and their weights to this Chart. I will reference it when I review the different cars for the layout. The heaviest cars are on top.
Numbers in Blue type are under are under the NMRA Standards.
Numbers in Red type are OVER NMRA Standards.
Last Updated: 03/23/23
| Manufacturer | Model | Car Length | RP Weight | Actual Weight | Over / Under |
| Lionel | Three Bay Hopper (H43) | 12 in. | 17 oz. | 40 oz | +23 oz. |
| Atlas O | Fishbelly | 8 in. | 13 oz | 29 oz | +16 oz. |
| Atlas O | War Emergency Hopper | 8.25 in. | 13.25 oz | 26 oz | +12.75 oz. |
| Lionel | 50 Ton Offset | 8.5 in. | 13.5 oz | 26 oz | +12.5 oz. |
| Protocraft | SP 50 ft Boxcar | 12.5 in. | 17.5 oz | 28 oz. | +10.5 oz |
| All Nation | 50 Ton Offset | 8.5 in. | 13.5 oz | 21 oz | +7.5 oz. |
| Overland | PRR H32 | 13 in. | 18 oz | 22 oz | +4 oz. |
| Atlas | PRR H21a | 10 in. | 15 oz | 18 oz | +3 oz. |
| Kohs | PRR GLe | 8 in. | 13 oz | 16 oz | +3 oz |
| Tangent Scale Models | GATC 6,000 Gallon 3-Compartment tank car | 8 in. | 13 oz | 14 oz | +1 oz |
| Lionel | PRR GLa | 8 in. | 13 oz. | 12.5 oz | -0.5 oz. |
| MTH | Fishbelly | 8 in. | 13 oz | 12 oz | -1 oz. |
| PSC | PRR GLa | 7.75 in. | 12.75 oz | 11 oz | -1.75 oz. |
| PSC | PRR H31 | 8 in. | 13 oz | 11 oz | -2 oz. |
| USH | PRR H25 | 10 in. | 15 oz | 13 oz | -2 oz. |
| Yoder Models | PRR GLCa | 8 in. | 13 oz | 11 oz | -2 oz. |
| Yoder Models | PRR H21a | 10 in. | 15 oz | 13 oz | -2 oz. |
| Yoder Models | 50 ton Offset | 8.5 in. | 13.5 oz | 11 oz | -2.5 oz. |
| Atlas O | USRA Twin | 7.75 in. | 12.75 oz | 10 oz | -2.75oz. |
| Yoder Models | PRR GLa | 7.75 in. | 12.75 oz | 10 oz | -2.75 oz. |
| Atlas | USRA Pannel Sides | 8 in. | 13 oz | 10 oz | -3 oz. |
| Weaver | B&O M-53 | 10 in. | 15 oz | 12 oz | -3 oz. |
| MTH | 50 ton Offset | 8.5 in. | 13.5 oz | 10 oz | -3.5 oz. |
| MTH | War Emergency | 8.5 in. | 13.5 oz | 10 oz | -3.5 oz. |
| Atlas | TM 70 Ton 9 | 10.75 in. | 15.75 oz | 12 oz | -3.75 oz. |
| Intermountain * | USRA Twin | 7.75 in. | 12.75 oz | 8.5 oz | -4.25 oz. |
| Intermountain Kitbash * | RDG Quad | 10.75 in. | 15.75 oz | 10.5 oz | -5.25 oz. |
* Kiel Line Weights added