As best as I have been able to figure out, Lionel changed from the 400E style brush tube to the 700E style brush tube when they started using brushes with shunts on them. Maybe some time in 1938. The brush tube with the cap gave them a way to clamp the washer at the top of the brush spring that the shunt is attached to. This gives a good electrical path from the shunt into the brush tube. I have not seen the 700E-35 part number before. I wounded if it is a typo of the 700E-305 part number. There are lots of errors in the part lists.
The 227 family of locomotives are great locos. It is too bad they did not make it into the post war era. I recently ran into a set of wheels which I am sure came off a 227 type loco. They did not look right and after studying them I discovered they had been insulated for two rail operation. The flanges and tread were scale size, even smaller that the tires that came on the 701. They had the cam on the back that operated the valve gear. I wonder what happened to the loco they came off of.
