I have a lot of experience with Atlas switches. I suggest that you get a simple voltmeter and check that all of the third rail sections are powered throughout the switch. You may have to run a jumper from a powered third rail section to the dead third rail section. Atlas switches, especially the older ones, are notorious for not passing power to all the third rail sections.
Another problem that seems to plague these switches is dirty track - especially the third rail. I have found that just cleaning the track on the switch will allow engines to pass over them. The switch can be dirty even when the other track is clean and engines are running fine on the rest of the track.
Another problem may be that the wheels are contacting both the outside and middle rail at the same time. This happens on some engines and not others. This causes a short which stops the engine without tripping the power supply circuit breaker. The way to find this problem is to turn off the room lights and watch for a spark as the engine goes through the switch. You can see this best when the engine has some speed. Place a short piece of insulated tape on the rail where you see the spark to see if this solves the problem. Several of my switches have pieces of insulating tape installed on the running or center rail.
A third problem that happens with all switches is that some engine rollers are spaced so that both are on insulated parts of the switch. Sometimes this can fixed by turning one or more of the engine rollers around or installing an extra roller on the engine.
If all else fails, you may need to use a relay to power one of the running rails depending on which way the switch is thrown to fix this problem. This is a last resort solution and requires connecting the relay to the switch machine. Try the other solutions first.
NH Joe
