I picked up my first Marx 333 locomotive without a tender and noticed that I was having some potential compatibility issues on my standard track turns... there wasn't enough movement in the couplers allow a successful pass of a turn - which causes wheels to come off the track. I tried a few different Marx tenders of mine out on it and I really didn't have a ton of luck on any of them.. I noticed the tender that normally comes with the 333 (3991 NYC?) has a unique coupler.. which may resolve the problem.
Do I need to grab the matching tender to run this train or should any Marx tender do the job? I figured it might be best to ask this question prior to fiddling with readjustments.