Large Scale Central

Spectrum 3 truck shay surging

Problem Solving
#1

Hi folks,

I have a very low mileage Spetrum 3 truck shay that recently developed a surging problem primarily in reverse. The locomotive is powered by battery and is controlled by Airwire. The power pickup leads have all been severed to avoid powering the track. I left the spring loaded contacts in place to transfer power from the loco to the trucks as it was done by the factory. I suspected these connections had gone bad, so I dissaembled, cleaned, and lubricated the points again. Still I am having the same problems with surging in reverse.

Has anyone else had this problem? I’d truly appreciate some experiences or ideas on this.

I had a similar problem with my Climax loco, in which the contacts had failed and were causing the front truck to stall occaisionally. It was easy to replicate the problem in the shop, so I was able to diagnose the situation easily. I ended up hardwiring the climax trucks to the main circuitry of the loco to avoid ever having this issue. I worry the problem with the shay is more complicated than this.

Thanks for any help!

Jeff

#2

Yes I know about the problem.

Unfortunately due to recent personal attacks, I won’t reply on the forum with the solution.

email me if you wish.

Greg

#3

Thought you had broader shoulders than this, Greg. Don’t let the bastards get you down. I don’t.

#4

Greg - I’m with Steve. You need to consider who is doing the talking; then adjust the noise threshold.

#5

My 2 truck had a surge problem. Per Dave Goodson, I hard wired the trucks and then lubed the trucks and all running gear. I also removed all the track pickups and wiring in the trucks. No more problems.

Terry

#6

Hi Terry,

I had that problem with the Climax, but I’m not seeing quite the same symptoms with this engine. As I discussed with Greg, I believe one or more of the worm drives has too much slop, causing it to cycle in and out of a binding condition. I plan to rewire the engine anyways, so the theory will be tested at least. I think drag from the simulated drive line has led to problems with the front truck (ONLY THE FRONT TRUCK DRIVES THE RUNNING GEAR). My first course of action is to swap the trucks around, allowing a different block to drive the driveline. Once this is complete I wil, test drive the loco to see if there is improvement.

#7

One, remove the spring pluggers and balls. 2, remove any electrical connections from the pluggers. 3, Uncover the blocks, one at a time, check all the gears and bearings and lube them well. and now test it on LEVEL track!

Paul

#8

I don’t think you can swap the trucks without major surgery due to the fact the drive gear runs down the right side.

Mine would surge on flat ground as well. For mine, the culprit was old dry grease in the gears that was making the gears bind. The contact rings were in rough shape too.

I hope you figure it out, it’s a bummer when your trains don’t work the way you want them to.

Terry

#9

Paul,

Does your step 1+2 essentially mean hardwiring the motors to the Airwire RX?

Terry,

Once you remove the the power brick from the sideframe (6 screws) I think they are all the same. Hopefully that is true…

#10

Update:

I tried swapping the front truck with the rear truck to test my theory, that perhaps the driveline had caused the issue. Unfortunately, the truck swapping did not solve the surging issue on level track.

Upon Greg’s suggestion, I tried deactivating one of the trucks. To do this, I took two of the wheelsets and swapped the wheels around so that the drive gears would no longer engage (yet the outside driveshaft bevel gears were still on the correct side). This allowed the truck to free-roll…to be sure, I also disconnected the motor leads just in case.

I suspected the original front truck (now under the tender) was the culprit, so it was the first truck to be deactivated. Since the locomotive has plenty of weight, I wasn’t too worry about the loss of traction having only 2 trucks powered. I also figured I would make up for it in longer run times.

Unfortunately, the tender truck wasn’t the bad truck. So, I reactivated the tender truck and moved on to deactivate the front truck, and then the middle truck. Saldy, all three combinations failed to relieve the surging. Therefore, it would seem I might have more than one “bad” truck…Now surely I wouldnt want to run the 3 truck Shay on only one powered truck…correct?

So for my third act, I decided I would completely rewire the power trucks. I ran a bus line directly frommthe RX in the tender to each power truck. I installed plug connectors at each truck (dircetly to the copper motor leads) to enable them to be easily removed. While doing this, I came across some lose connections between the motors and the circuit boards on each truck. I ended up removing the the circuit boards since the motors were now directly wired to the plug connectors, so I felt I was really on to something!

Once again, I was let down. The locomotive surged just as poorly with the simplified wiring, as it did before.

I had one more idea to try out today. I thought, perhaps my Airwire RX was malfunctioning, causing the loco to surge. To test the theory, I disconnected my newly created bus line, and hooked it directly to a 9v battery source. This allowed the loco to travel at a moderate speed for testing. Sadly, the loco surged just poorly as it had before.

Anyone want to buy a Shay?

#11

Do you have surging only running it with track power?

The RX might be your problem.

#12

Hi Dennis,

Thanks for the suggestion. While I can no longer run the engine on track power, I was able to disconnect the onboard battery and RX and run the engine directly from a separate 9v battery. Unfortunately…the surge persists.

My latest theory is that the worm drives are not fully engaged, (as deeply they are on other brands). I think this could be the result of a slight misalignment of the gear train in the diecast housing. I’m not yet sure if this can be adjusted, but it would seem to me, the more gear teeth engaged, the tighter it would run.

I suspect replacing the plastic gears (which mate with the worms) would solve the problem. Unfortunately, if that works I can plan to do replace them every other year or so. Do you suppose its the same gear used by Aristo and USAT?

#13

Rockwall Canyon Jeff said:

Hi Dennis,

Thanks for the suggestion. While I can no longer run the engine on track power, I was able to disconnect the onboard battery and RX and run the engine directly from a separate 9v battery. Unfortunately…the surge persists.

My latest theory is that the worm drives are not fully engaged, (as deeply they are on other brands). I think this could be the result of a slight misalignment of the gear train in the diecast housing. I’m not yet sure if this can be adjusted, but it would seem to me, the more gear teeth engaged, the tighter it would run.

I suspect replacing the plastic gears (which mate with the worms) would solve the problem. Unfortunately, if that works I can plan to do replace them every other year or so. Do you suppose its the same gear used by Aristo and USAT?

Well it was a shot anyway. I have 2 Shays but both have the revised V2/3 trucks. First time I have heard of the metal truck problem.

Was going to convert them to the new metal ones and now will delay that option.

#14

I’m pretty sure that all the Shays surge on a downgrade to some extent, it has to do with slop in the worm gear that one fix or another has been proposed at one time or another with little or no effect.