Hi Rick,
I still participate in all the forums where I used to (except for Atlas, of course). I just don't participate as much, and have moved on to N scale shipbuilding. which presents a whole new set of problems that are best discussed on ship modeling forums--except, in many of the things I am trying, there are no answers yet. That, and caring for Kay the past eighteen months, doesn't leave me much time to surf.
I have extensive notes about my torture tests, but they are buried in boxes still. I never considered it torture testing, as I never overloaded an engine consist, nor ran it more than 45 smph. I spent a few nights with a stopwatch/lap timer, timing laps that were about eight minutes on the Pittton and 40 minutes on the Portsmouth. I was going to put a sensor on both layouts, courtesy of my older brother, and hook it up to a retired computer, to make data acquisition and crunching easier, but I decided that was just a little beyond sensible. I may have posted a data table somewhere (probably on the old-old Atlas), but I can't remember, and I probably just posted an analysis of the differing lap times on the Pittston. Or wrote it and didn't post it, as I couldn't make sense of it or draw any conclusions.
Also, I was pretty busy with business those days.
Here's what I remember about the Pittston trials. There were 200 linear feet of track, at least half of it 2.5% grades. I would set and forget a consist while I worked on a project at my worktable below the layout. There was a milepost, and the train made enough noise that I was alerted when it was approaching, and clicked the stopwatch at the post. As I remember, the laps were about eight minutes, probably ranging from 7:50 to about 8:20, with a few outliers on the longer side of perhaps 8:40. I let them run until I got back the next morning to time a few laps, then let them run and timed a few more laps at night. The variation just didn't seem significant to me.
The Portsmouth Branch, with an average run of about 45 minutes, was even more consistent.
My conclusion: except for the cracking gear problem on the Bachmanns (which foiled my efforts at making a Baldwin Centipede out of the DD-40Xs you traded me), the diesels will essentially run about forever at the same speed--with basic maintenance.