I'm pretty sure they work with these:
Lionel Post War style lighted bumper. (I don't have a picture handy that I actually took of one, that's why I linked vs posted the pic itself.)
Slight variations of these were made in the Postwar, MPC, and even modern era, they fit on tubular O Gauge track. Doesn't' do you much good though if you are exclusively FasTrack, of course. I believe someone wrote a post recently describing how to modify them to work with FasTrack, but it's a bit of an effort.
The FasTrack lighted bumper you show may technically fit the bill, but I'd be really hesitant to repeatedly slam these handcars into it, with all the problems the lights on these have had (particularly early runs).
I'd have to agree the FasTrack earthen bumper is not appropriate due to the challenge you described.
As frustrating as this may be, it should be noted that Lionel never made handcars with this reversing mechanism, that's only been done by I think MTH and also Industrial Rail (not sure if Atlas re-did the hand car when they bought the Industrial Rail line of products). So we are asking a Lionel product to be compatible with something they never offered for sale.
-Dave