Gross weight and truck size

[daniel_leavitt2000]

I'm trying to see what cars in my collection need 100T trucks. I know that's tied to the gross loaded weight. What is the magic number that requires 100T trucks? That's the weight limit number on the side of the car, correct?

[wazzou]

Usually anything beyond 140,000 #'s that exceeds 70T trucks, right?

[daniel_leavitt2000]

Yep that sounds about right. I forgot the number and couldn't find it doing a search. Now in to reading 1300 REALLY tiny sets of numbers.

Thanks man!

[PGE_Modeller]

Truck size determines what the maximum gross weight, the sum of the Load Limit (LD LMT) and the Light Weight (LT WT), of the car can be.  For a nominal 100 Ton car, this maximum gross weight (from the 1953 Official Railway Equipment Register) was 251,00 lbs; for a 70 Ton car it was 210,000 lbs; for a 50 Ton car it was 169,000 lbs; and for a 40 Ton car it was 136,00 lbs.  These maximum weights were increased in the modern era and I do not have that information as it falls outside my era of interest.  Photographs of modern era freight cars should provide the answer, however.  Visually, from a modelling point of view, the appearance of the spring package and the truck wheelbase depended on the capacity of the truck.  In general, 50T trucks had a 5'-6" wheelbase, 70T had a 5'-8" wheelbase, and 100T had a 5'-10" wheelbase.

Cheers,

[nkalanaga]

Maximum weight for a 100 ton car since the early 60s has been 263,000 pounds.  All of the weights were increased in the early 60s, with the nominal capacity of 50 and 70 ton cars going to 55 and 77 tons, respectively.  Anything over 220,000 lbs, up to 263,000, used 100-ton trucks.

If you have a lot of the old MDC 70-ton trucks, they can be converted to 100-ton easily, and look quite presentable.  They would be a couple inches short, but on many cars that's an advantage, as Atlas or IM 100-ton trucks can have clearance issues.

All it takes is to replace the wheels with 36 inch, MT wheels work fine, so anything with the same axle length should work.  Then shave the raised ring off the top of the bolster, and the car will sit at the same height it did before, no need to adjust the coupler.  If true 100-ton trucks aren't available, or cost is an issue, it's an option.  I did it on quite a few of my hoppers and covered hoppers, that already had the MDC trucks.