Malc, thanks, I do prefer emails because I see them, I don't look normally look for PMs.
About the Engine specs. There are two types and they are not interchangeable. We dedicated two locos to the sessions as we found that as the DHR is a 'dark route' with no signals, AI drivers drove at caution all the time, ignored the speed posts, and would not drive faster than 8 mph. To overcome this I had to increase the loco mass by 10 times (100 ton locos) and this overcame the problem. Don't ask me why, it just did. If you haven't seen any speed posts, they're there, just invisible.
I will see if I can sort the problem out will and report back.
Peter