First and foremost, sorry to hear of your brother's passing.
For a historical perspective on the 3rd E7, the 2011 E7s were the first plastic shelled diesels 3rd Rail had ever done. They had some issues, but overall were very good locomotives. My one 3 rail E7 has provided me with good service All my other E7s from that era are 2 rail O. The issue with the speed may have to do with the belt that connects the motor shaft to the drive system below. It is just like a little timing belt being geared. If it has not been run or run in many years it may just need some breaking in, or perhaps look at it see that it hasn't slipped at all. Overall the belt system is louder than the vertical can motor setup, but the gearing ratio is superior for pulling with the 3rd Rail drive. There are some plastic drive parts in the original E7s that did occasionally break in the original E7s. 3rd Rail may still have replacement parts made of steel as that was the first upgrade to the drive system which is now in its 4th generation I think.
3rd Rail diesels do top out at about 60 smph which was a decision made early on as 60% of the 3rd Rail market is in 2 rail O which tends to generally run trains at slower speeds. Replacing the TMCC with PS2 or PS3 is not difficult for someone skilled at those modification. Getting the trailing locomotive to start in reverse is a TMCC command function.
Good luck and enjoy! These still command in many cases close to list value on the secondary market. The cars are difficult to find. A majority of my trains are now Sunset / 3rd Rail / Golden Gate depot now.
