An early version Aristo-Craft Southern Pacific RS-3 refitted with ball bearing motor blocks and increased weight for improved traction is tested in a train on my layout. The train first exits from under the house and then traverses a double loop to gain elevation to reach the upper part of the layout.
If watching on Youtube, High Def resolution can be selected.
https://www.youtube.com/watch?v=81M3aRb6Hjc&feature=youtube
Though the SP RS-3 can pull the 26 car train on level track, the train uses two locos so it can pull it up grades and around loops. The SP loco is an early version unit refitted with Aristo’s (no longer available ART-29139) ball bearing blocks having stainless steel wheels of reduced flange depth. The other Rock Island loco is a relatively late version unit having factory ball bearing motor blocks with conventional deep flange wheels and increased factory weight.
-Ted