Lionel train problem

Are you using TMCC or Legacy? Is there a metal bridge, parallel tracks or tracks that crossover (elevated)?

Adding to what cbojanower asked.......does this "certain" point involve a turnout? Is it possible you have one dead pick up roller on this engine?

Check for continuity between the rollers with an ohmmeter. If they are OK, move on to the next experiment:

Measure the exact center-to-center distance between the rollers, then position the loco at the exact spot that it loses power. Make marks on the center rail and use a ruler to see if there's a relationship between the marks and the roller dimension.

If all is well, there may be a running rail problem, where an outside rail is losing continuity.  A meter and a test lamp will help find it.

make sure the undercarriage of the train is not shorting itself at that point of the track.

Pete

I am using Legacy. I just installed a Bascule bridge on that loop of track; and the spot where the locomotive stops is near a turnout but not on it.

depending how close the bridge is to the problem area and its its a lot of metal you will want to connect the metal in the bridge to a earth ground. It could be causes enough interference that the engine is loosing signal. Also make sure the track is not touching the metal of the bridge.

As for the engine see if the contacts are finding a dead spot. Maybe remove the shell and see of the antenna wires have come loose

Does the head light flash or does the engine lose power? Headlight flash indicates TMCC signal problem. Dead engine indicates power issue

the headlight does flash when it stops at that point

In addition, the engine still runs, but I have to rev it up to get it going again. But despite this, all my lighted cars go past that point and do not flicker

Headlight flashing indicates TMCC problem. I would try laying a grounded extension cord near your track where the issue lies. (plug it in) See if the train can pass that area. Also try running a ground wire from the metal part of the bascule bridge and wire it to the ground jack of an outlet (do not allow power to be plugged in)

Good luck

Chris

You were right on. when I connected  a grounded extension cord to a socket and laid it near the track, all the flickering of lights stopped and the engines rode smoothe as silk.

Thanks for the excellent advice

Stu

So all you have to do now is to hide a stretch of wire along that section and ground it for a more  permanent and hopefully better looking fix.

You can hide it in the ground or some people have made phone lines out of it