I'll give it a try. Most of the electric locomotives the Milwaukee had we built in the teens and soldiered on thanks to the shops and mechanics of the Milwaukee road. No new electric locomotives were added until the time of the Korean war. General Electric built 20 locomotives that were slated to be sold to the Soviet Union, but due to the cold war, the deal fell through. These locomotives were to become the EF-4 and EP-4 locomotives for the Milwaukee Road, better known as the "Little Joes". The Milwaukee bought 12, the Chicago South Shore and South Bend bought 2 and the remaining 5 went to South America. Fourteen had to be rebuilt from the 5 foot guage of the Soviet Union to our 4 foot and 8 and a half guage. These locomotives almost went to scrap.
These locomotives were used in the Rocky Mountain Division between Harlowtown, MT and Avery, ID. These giants continued in service for a couple of more decades until diesels were showing up under the catenary. The Joes were used as helpers many times running along with diesels, and with the smarts of the Milwaukee shops, were also controlled by the Joes. There were no plans for modernization that I was aware of for the overhead or powerhouses. The powerhoues were still performing just as they had when they were built. When Passenger service ceased in 1970, the Milwaukee was thinking about de electrifing with diesels being the main power. The powers to be at the time seemed to be trying to run the Milwaukee road into to ground. The electric operation ceased in June of 1974, right when the "73 oil crisis really hit. The copper from the catenary did provide the road with some much needed cash, but due to more bad decisions, the Milwaukee went into reorginizayion in 1977, but never recovered and was finally taken over by the Soo. In 1984 the Milwaukee Road ceased operations here in Montana.
The photo shows a typical lash up of electric and diesel. The picture was taken at Saint Regis, MT, crossing the Clark Fork River. In the background you can see the Northern Pacific' rails. The bridge is still there today, and can be seen from I-90. Driving along I-90 in western Montana you can see the old Milwaukee right of way running right along side the now BNSF rails, with many of the bridges and tunnels easily seen.