Thanks Mark and Bruce!
Mark: to do a comparison of the frame on your 6-28005 to mine above, you would have to remove the shell (maybe not a good idea if yours is running well) and see the structure of the frame ahead of the motor. I looked at the parts breakdown here of : https://www.lionelsupport.com/...1e-892c-122e205144e3 and looked at the frame - item 31 - and it looks like it is shorter but too dark to see what is there ahead of the motor.
Bruce: took a look at the rear truck and the spring there pushing it down is really weak; bet a stronger one would be better; something to consider along with a bit of weight up front. Oregon!! Here in Fla it was 74 today. Now, where can one get springs?