The "average" train "tonnage", length, or number of cars is probably unknown, unless you have the data to calculate it. But, "typical" LA Division mainline trains in the 70's and 80's were usually between 5,500 and 8,000 feet over Beaumont, and in and out of Taylor, and between 4.000 and 7.000 tons depending on load/empties and train commodity make up. This often meant trains of 70 to 120 cars. Beet trains and ore trains came in at 10,000 tons. On the "haulers" and locals it varied quite a bit.

As Zark noted, I've also had some "whoppers", outside those "normal" parameters, including a 140 car "hospital" train of "wounded" bad orders out of Indio, mostly empties for scrap (a Purdy special), leaking air, and awful to handle, that, as noted, couldn't take most sidings, and tied up the entire hill, when we finally died on the law, just trying to get from Indio to West Colton.

One of the more notoriously goofy operating officers at West Colton often also tried to put together "mega" trains out of West Colton in the mid 70's to LA, to save crew costs, which caused nothing but a mess for the dispatcher, who had almost nowhere except Pomona or Industry to put these usually low priority turkey's into.