My son and I model primarily Southern Pacific. We have a 'boat loads of 'Balck Widow' era locomotives (everyone ever made by Proto 2000, a couple Stewart F Units, and Kato Units). We also model 'newer SP' stuff (Scarlett and Gray). Sp was fairly famous for it's 'Tunnel Motors' (SD40/45-2T's). Athearn makes the only ones in HO scale (to my knowledge. Unfortunately, they all run very noisey (as compared to msot of are other locmotives). You can hear their drive train gearing 15+ feet away! I'm in the process of converting two SD60 Proto 2000 frames (with motors, trucks, weights and circuit boards) to SD40-2T's (using Athearn shells) in order to get quieter SD40-2T's. But I will still have several more Athearns left and really cannot afford the time or money to do all of them this way. I, therefor, need to find a wayu to make them run quieter. I've tried the following:
1. Replaced the Athearn wheel sets with Northwest Shortline Nickle Silver sets.
2. Replaced the Athearn Can motors with A-line can motors and weighted cradle mounts, flywheels and drive shafts.
3. I've bought all new truck assemblies (Athearn)
4. Followed all the Athearn tuning tips in various publications (removing 'flash' from the gear sets, etc).
5. Polishing the gear sets with "Pearl Drops" tooth paste and then thoroughly cleaning the gear sets.
6. Adding gear grease (white) to the gear sets (so far has given the best results, but they run a little warmer now; not too much warmer; definately nohwere near the F units mention by the one member).
7. I've gone through several sets of drive trucks (front and rear) for each engine. I do not continue with the same trucks after I've tried various 'tricks' that failed. Even the brand new trucks run rough. You can feel it when you 'hand roll' them on the track before they are installed in the locomotive(s).
I was hoping, after reading the exceptional help given to the guy with the 'hot running Athearn F-unit motor), that someone might be able to give me some ideas or advice to help these Athearn 'Tunnel Motors'. If some other company made them, I would slowly (as money permitted) replace them, but you really cannot beat Athearns's $35 price tag for these (that is how much I find them for brand new on a regular basis). Can't run Southern Pacific in teh 'Bloody Nose era' without these. When detailed, they really look great.
We have decoders installed in all of them, as we now run all of our stuff on DCC. They are just as noisy now as they were before the decoder installs (decoders will not fix or cause gear problems).
I have narrowed it down to 'gear slap' in the trucks. if I run the locomoitves with only one truck 'drive shafted' to the motor, they run quieter (doesn't matter which truck). As soon as the other truck is 'drive shaft connected', the noise starts. It's like the trucks are "fighting each other", even though they are both connected to the same motor.
We ultimately would like to put sound decoders in them as we slowly convert some of our stuff to sound, so this gear train noise is something that will need to be solved. We've also been 'spoiled'by the smoothness and quietness of the Proto 2000, Kato and Stewart Diesels we have as well as the many steam engines.
Any ideas?
thanks,

1. Replaced the Athearn wheel sets with Northwest Shortline Nickle Silver sets.
2. Replaced the Athearn Can motors with A-line can motors and weighted cradle mounts, flywheels and drive shafts.
3. I've bought all new truck assemblies (Athearn)
4. Followed all the Athearn tuning tips in various publications (removing 'flash' from the gear sets, etc).
5. Polishing the gear sets with "Pearl Drops" tooth paste and then thoroughly cleaning the gear sets.
6. Adding gear grease (white) to the gear sets (so far has given the best results, but they run a little warmer now; not too much warmer; definately nohwere near the F units mention by the one member).
7. I've gone through several sets of drive trucks (front and rear) for each engine. I do not continue with the same trucks after I've tried various 'tricks' that failed. Even the brand new trucks run rough. You can feel it when you 'hand roll' them on the track before they are installed in the locomotive(s).
I was hoping, after reading the exceptional help given to the guy with the 'hot running Athearn F-unit motor), that someone might be able to give me some ideas or advice to help these Athearn 'Tunnel Motors'. If some other company made them, I would slowly (as money permitted) replace them, but you really cannot beat Athearns's $35 price tag for these (that is how much I find them for brand new on a regular basis). Can't run Southern Pacific in teh 'Bloody Nose era' without these. When detailed, they really look great.
We have decoders installed in all of them, as we now run all of our stuff on DCC. They are just as noisy now as they were before the decoder installs (decoders will not fix or cause gear problems).
I have narrowed it down to 'gear slap' in the trucks. if I run the locomoitves with only one truck 'drive shafted' to the motor, they run quieter (doesn't matter which truck). As soon as the other truck is 'drive shaft connected', the noise starts. It's like the trucks are "fighting each other", even though they are both connected to the same motor.
We ultimately would like to put sound decoders in them as we slowly convert some of our stuff to sound, so this gear train noise is something that will need to be solved. We've also been 'spoiled'by the smoothness and quietness of the Proto 2000, Kato and Stewart Diesels we have as well as the many steam engines.
Any ideas?
thanks,
