Discussion relating to the PRR, up to 1968. Visit the PRR Technical & Historical Society for more information.
  by SSW921
Allen Hazen wrote: Fri Jul 12, 2019 1:44 am Re: about E8 and E9: "Both units used the Blomberg A-1-A truck." E units (like many other things...) got heavier over their history, and (as Preston Cook pointed out in his E-unit series in "Railfan and Railroad" a few years back), later Blomberg A-1-A were more robust than earlier. (Difference in frame thickness is visible ... if you know what to look for.) I don't know whether the adoption of heavier frame trucks coincided with model change or not. And many late units ran on earlier trucks.
Just to make things even more confusing!
The Pennsylvania E8As tipped the scale at 335,000 pounds, there were very few that weighed more and only by a few hundred pounds.
  by SSW921
This is a theory, based on some known facts and a little supposition on my part. The Illinois Central had two E9As on order in the Spring of 1954. This was part of EMD order #2062A for serials #19371-19372. This order was cancelled, likely that Spring. What Illinois Central did was a trade in of E6A #4004, that unit was removed from the roster in May 1954. A single E9A was built for Illinois Central on trade in order #7517. Illinois Central E9A #4036 was EMD serial #19608 built in June 1954.

I don't know the details of what caused the demise of IC #4004, was another unit involved?

What if the Illinois Central was already committed to the two E9s, but changed it to one. The cancelling of order #2062 and the trade in of E6A #4004 suggests that is what happened. The other unit would then be available for another railroad. Trade in order #7518 is blank.

It's only a theory . . .

Ed in Kentucky