Rebuilding locomotives just in time for show season!

I haven't been posting much lately, kinda burned out on social media and took a break from Lego for a little while. However, with the summer show season fast approaching, it was high time to get to work on a variety of things! Not least of which, repairing my fleet. I've been trying to run my ore train at shows for over a year now, and every time the locomotives (first pic) crap out after a few minutes. Tore apart both 636's down to the frames (second pic), and rebuilt them entirely,...