Interesting; just checked the MTL website and discovered that all mention of truck replacement for the Bethgons has been removed. Just as well I still have my copy of MTL/Kato conversion Excel spreadsheet I downloaded from MTL in 2006 - replacement truck for the Bethogon is the 1030, which is what I've fitted to mine.
What's the difference between the 1030 and 1035? Looking at the chart (http://www.micro-trains.com/Truck diagrams.pdf) they seem exactly the same to me. Edit: Scratch that, I see it. But isn't the 1030 a 70-ton truck, while the prototype bethgon has 100-ton?
How many trains are really perfectly one set of paint schemes anyway? I had the same problem with my Kato's one one curve. It also had a small twist in the rails that had developed over the years, but MT's worked fine in the same area. I suspect your Unitrak is perfectly aligned, though.
