Bachmann HO loco, 1970's EMD F9A Santa Fe w/ original old brass like track. The loco has been running fine on my layout for a couple weeks. It had been in storage for a few years. Light use since 1970, mostly run around the holidays every few years. There are two places on my layout where the loco slows down, and almost comes to a stop. The loco light goes dim at both those places. My immediate thought was a track problem so I replaced track pieces at those two places, but same problem. I don't have another loco to test. Also there are two different places on the layout where the loco makes a noise when passing. Two different places from the places it slows/stops. Weird. All this happened at about the same time. So now I think it is the loco since the sound is a bit like the sound a Thunderjet 500 car pancake motor makes when it needs oil. But I only have a little experience with train motors. I have oiled the loco in the two pin holes at the top of the chassis, plus a tad on the truck gears. Still slows/stops & makes noise at same places on the layout. One of the places the loco slows/stops is on/near the straight piece where the power pack connects. I've checked that connection and checked the metal tabs that touch the rails. All looked OK. The other place the loco slows/stops is near the straight car/train crossing track piece that came from Aurora Model Motoring years ago (for use with my Aurora Tjets/Bachmann train). It has always worked fine, and I use it as a rerailer too. Any suggestions or tips for trouble-shooting this further would be appreciated. Thank you.