The button is on the outside of the straight section about 2" from the end of the rail.

I can't find any pictures of the new remote switches. Odd...

I looked as well Chuck, that's why I dropped into text mode.

Here, I made a picture.

Thanks. I looked at Lionel Products, etc and found it funny there were no pictures, and parts was not helpful. I see why, it's tiny! They had a picture of the push button but no size reference.

Think I'll get one to mess with.

I guess the point was to make it so it doesn't stand out.

If you ever have one of those little pushbuttons die, you'll find out that they don't have replacements for them at Lionel.  To add to the fun, they're very cheap switches, so they're quite likely to die.  I've replaced a couple for people, I found one that could be made to fit at Digikey, but I had to enlarge the hole slightly for the fatter stalk on the replacement.

Wonder if the button comes apart. I found those tactile smd push switches on the bay that go in the legacy handheld under the red button. Might be the same. 

It's a cheesy little button, the same type you find in $2 toys at times.  I had several, but I needed one with the longer stalk for where it mounts.  Now I have a couple of spares.

Gunrunnerjohn,

   Thanks much for the knowledge John, if any of mine go bad I will come back to you for the exact switch button required for the fix.

cjack,

    If you do not mind telling me, what did you have to give for the 072 Command Control FasTrack switch. Interested to see what you had to give for a used one.

PCRR/Dave

You can have it right now.

ADTSM65NVTR

This one fits perfectly, you just have to enlarge the hole a bit for the plunger.