The train feat puts him well above people like Fox Colossus, in strength, as well (stopping train >>>>> throwing a tire or shifting some concrete). But then, he already showed some serious strength when he broke the Waverider, by smacking Ray into the one wall. That ship has taken some horrific impacts and only sustained minimal damage. Steel knocked a friggin' wall loose, so that the inside was exposed to the outside.
Not to mention, he crash landed and left a decently-sized crater, like an asteroid, without taking any damage. That's also an extremely impressive durability feat.