How use test stand with MTH DCS

Hi OGR members:

Recently purchased Chuck's test stand on eBay to primarily test MTH Subway engines. Stand uses alligator clips that relay power from lionel track on the test stand to power unit connected to a transformer. My setup consists of a MTH DCS Controller/TIU/Z1000.

Alligator clips are placed on power unit as follow, red clip on pick-up roller and black on nearest wheel which are clipped on the other end to a Lionel track on the test block. This presents a problem when unit is powered in conventional mode as you can imagine with black clip falling off when wheels move. Does anyone have a better suggestion of placing black clip so wheels can move freely without removing chassis to find a better ground?

see if frame itself is grounded for your black clip.

My other problem is getting a DCS controller to find engine to operate it in command mode to test run engines in auto mode. Hoping someone can easily identify my problem. Thinking it has to do with either how I am placing the clips or possibly the fact engine is not on tracks. DCS controller simply cannot find the engine.

from pictures I see no power to the tiu try powering the aux power for tiu then watchdog signal will be on track and tiu will find that unit.

Any suggestions is greatly appreciated.

Bill