I think on 0-27 switches it is more likely that you are getting momentary short circuits. Watch it close to see if you are getting arcing Under the loco when it goes through a switch. Usually a little piece of electrical tape in the right place corrects the problem. Lionel has a long history of tender connections to the loco. This mostly had to do with long gaps on 0-72 turnouts or outside third rail. The tender to loco connection on two rail equipment usually had to do with power from one rail picked up by the loco and power from the other rail by the tender.