Replacing switch machines, or entire turnouts
VGN310;
You have several options.
First, you could try taking the Atlas switch machine apart and then cleaning & lubricating the inner parts. My 50 year old Atlas HO-scale switch machines were riveted together. If yours are, the rivets can be drilled out, but it's a pain to do. My 30 year old Atlas N-scale switch machines were stuck together, (So poorly that some shook themselves open just from the vibration of normal operation!) with internal plastic pins. Those that hadn't self-destructed could be pried open with an x-acto knife along the seam between the top & bottom castings.
Trying to repair these things has somewhat poor likelihood of succeeding, but since they're already broken, you don't have much to loose by trying. The internal parts are small and easily lost. One, or more, of the electric coils inside may have burned out. Is it worth it? That's up to you.
Second: You could do what CTValley suggested, and replace the Atlas switch machines with servos, Tortoise stall motors, Caboose Industries ground throws, or mechanical linkages. The file "All about turnouts" discusses these options and a lot more.
This approach assumes you want to keep your Atlas "Snap Switch" turnouts, and replace only the switch machines. The advantages would be saving the cost of new (and better quality) turnouts, and the fact that you would not have to alter the track geometry of your layout to accommodate the new turnouts. You see no other commercial turnout will be exactly the same size, and shape, of your present ones. The changes in track geometry are usually minor, and can be done by using some short pieces of flex track leading into the turnout.
The downside of Keeping your Atlas "Snap Switch" turnouts is that they are simply not very good turnouts. In fact, I, and lots of others, consider them to be the worst available. That doesn't mean everybody dislikes them. There are plenty of people who use Atlas "Snap Switch" turnouts, and like them. The attached file "Improving Atlas turnouts" shows some things that can be done to make the Atlas "Snap Switch" turnouts more reliable.
Third: You could, as prrfan has suggested, replace your turnouts with much better quality, more reliable, turnouts, like Peco turnouts. They have a well-earned reputation for high quality, reliability, rugged construction, and seldom, if ever, causing any derailments.
The plus side of this option, you end up with the best commercially available turnouts, instead of the worst.
The negative side is expense. You will have to bear the cost of the new turnouts. Also, you will need to take up, and replace, the track near the turnouts since the Pecos (or any others including Atlas's own "Custom Line" numbered turnouts) will be a different size & shape than the "Snap Switches" they are replacing.
I recommend the third option because, in the end, it will increase the reliability of operation on your layout, and your own satisfaction.
However, it's not my choice, but yours. Choose whichever option you like.
Traction Fan :smilie_daumenpos:
View attachment All AboutTurnouts rev 4.pdf
View attachment Improving Atlas turnouts pdf version.pdf