The attached PDF document shows, step by step, a way to modify Lionel No. 260 bumpers to convert from incandescent bulb to LED and to fit Lionel FasTrack.
I got the idea from this posting: http://cs.trains.com/ctt/f/95/t/228983.aspx but the photos no longer show there.
I wanted rugged bumpers for a children's layout for a railroad museum and the FasTrack bumpers just looked too fragile. Also, there are reports that the LED electrical connection is very unreliable.
Here is the finished result. It is VERY solidly mounted to the track at all four corners. (Orange colored light is just a camera artifact - it glows red.)
June 12, 2021 UPDATE: While the LED's specified are claimed to be rated for 20 mA, after some dozens of hours they were failing. So, the series resistance was increased from 680 ohms to 953 ohms to reduce the nominal current to 15 mA (a "75% derating" in electronic jargon). The attached pdf instruction document was also updated to show this change.
October 29, 2022 UPDATE: Even with the original LEDs chosen derated to 15 mA, they were still failing. So switched them to CREE diodes (reputable manufacturer) and added a comment on the page with the schematic in the attached instruction document. This is the LED now used:
CREE P/N: C513A-WSS-CY0Z0341 (CREE part number for a standard 20 mA bright white LED)
Mouser P/N: 941-C513AWSSCY0Z0341 (Mouser distributor part number)
