advtrains_freight_train (ContentDB) is a mod that adds 4 more types of freight wagons to the game as well as a slower diesel locomotive. All of the wagons and the locomotive are recoverable - they drop themselves instead of steel. The wagons also have a higher capacity of 48 compared to the standard 24 inventory slots.
The original art was done by mbb. The diesel locomotive icon and the horn are by Smacker, who has also done code maintenance on the mod.
Most recently added is a livery feature for the diesel locomotive to allow to be recoloured using the bike painter.