My new Restoration Big Boy (20-3807-1) is quite jerky when running at less than 6 scale mph. This engine is in reverse at 3 scale mph in the attached video. Is this normal very low speed operation for a MTH PS-3 steam locomotive or is something wrong with my new Big Boy? Maybe I’m spoiled by newer Lionel Legacy engines that are capable of very steady crawl speeds.
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dirty wheels, track?
MTH will never compare to Legacy for low speed control
In my experience, many MTH Steam engines and Diesels never level out smooth until after 5 MPH.
Thank you for your replies! The jerky low speed operation still occurs on straight track without switches. The wheels & track are clean and the engine has been oiled.
It is important to note that this engine does run VERY smoothly at 6 scale mph and above. In fact, it tracks much better through O-72 switches and “S” curves than my Lionel Legacy Big Boy, especially in reverse!
At very low speeds, those hesitation moments seem to occur at about the same 2 points in the drivers’ rotation.
Can you please post a close up picture of the end of the tether coming off of the engine. Trying to determine if there is damage to mine.
It has ro be broken in. Let it run at 3/4s speed minimum for about an hour. You can use rollers or have it haul a train.
As noted above it needs some break in time. Lube everything and run it for a couple hours at 25-45 mph. After that it should smooth out and run down to 3 or so MPH smoothly.
Aside from break-in, it looks to me that the brakes may be contacting the wheels at two times during the video - first the 4th driver on the rear engine and then the 4th driver on the front engine about 4 seconds before the end of the video.
Melgar, I wondered about the brakes hitting the drivers! When you say “4th driver”, are you counting from the front so that you’re referring to the rear driver on each engine? That would be the driver that has slightly more diameter due to the traction tire.
@Peter C posted:
Melgar, I wondered about the brakes hitting the drivers! When you say “4th driver”, are you counting from the front so that you’re referring to the rear driver on each engine? YES. That would be the driver that has slightly more diameter due to the traction tire.
Yes. Counting from the front driver and going rearward. It looks to me that at about 4 seconds into the video, there is no clearance between the brake shoe and the 4th (rearmost) driver of the rear engine and then at about 11 seconds into the video there is no clearance between the brake shoe and the 4th (rearmost) driver of the front engine. Again, counting from front to rear on each engine. Also, as others have said, the engine needs at least one hour of run time for break-in. Steam locomotives, with their multiple axles and connecting rods inherently have high driveline friction when new - and this locomotive has two engines... Check the brake shoes and then run it for an hour.
Possibly siderods binding, or brake shoe rubbing traction tire as previously mentioned. When i was at MTH i used a dentists mirror to see the siderods in motion from the bottom , usually it was side play wheels moving from side to side.