Lionel Jr. & FasTrack

Your best bet is to take a Lionel Jr engine and run it through a Fast Track switch.

The issue that Lionel Jr has with 022 switches is that the cast gear side of the drive wheel has the gear teeth at a larger diameter than the opposite side wheel flange. So the gear teeth ride lower than the wheel rides on the track rail. Going through switches, the O27/Lionel Jr. wheels ride up on the points of the switches on the gear side of the wheel. This causes a derailment or lifting the contacts from the track, etc. Anyway, the Jr trains get a bumpy ride through a regular 022 switch.

So much for the explanation as to what the mechanical issue with Jr. equipment is. Whether it is the same for the Fast Track switches, I don't know. You'll have to try.

The only other issue I could see is that if the Fast Track rails are much lower to the road bed than regular O gauge track rail to the ties, there is the possibility that the gear side of the driver may ride/rub on the Fast Track road bed.

Sorry I don't have a concrete yes/no answer for you. I just do not have any Lionel Jr/027 equipment any more.

I have a Lionel Jr. #1700 streamliner.  It runs fine on FasTrack, but doesn't like the switches at all. As jsrfo has said, the FasTrack switches interfere with the gear on the drive wheels.  Same for my Lionel #252.

I keep a loop of 027 track and switches reserved for my prewar equipment.

(Edited to correct a typo: it's a #1700, not 1400)

Marx O27 switches should work well - if they are the metal ones. the plastic switches Marx made sometimes work and sometimes do not.

I designed a 027 modular set up and one of the requirements is Marx metal switches. Not perfect, but better than most other options. Switches seldom cause us issues no matter the era we are running.

Steve

Exactly what is "Lionel Jr"?

I've been under the impression that it's what Lionel bought from Ives from 1928 onward.  I have a Lionel #1684; that's not Jr., is it?

Its wheel flanges strike bottom in 027 switches, causing the engine to jump.

I believe the problem is with the single reduction gearing.  One post war engine that has this problem is the 1654.  The 1655 is the same loco but with this problem corrected by going to double reduction gearing.  To make single reduction gearing work bull gears had to be very large and they extend below the top of the rail on the inside of the drive wheel.  This worked ok on the 1024 switches, which have movable closure rails.  When Lionel went to the 1022/1122 switches with frogs and guard rails, the gear hits and the loco bounces or derails.  It is also a problem with the 6019 remote control track.  Where the center rail curves out around the magnet in the center, the single reduction bull gear will hit the center rail and short.