I have 2 identical engines that I want to run in a lashup. One of the engines runs a good 5 to 8 SMPH faster than the other 7 PS2 engines that I have, including its twin.

I tried running the twins in a lashup last Christmas and it was obvious that it wasn't working. I recall reading here on this forum that the slower engine in a lashup should be the lead engine, so I did that. But the speed discrepancy in my case was too great I could actually hear the trail engine straining after about 5 minutes of running. I tried reversing them but it still wasn't working.

My only thought at the time was to clean the speed sensor tape that goes around the flywheel, so I did that but it didn't help.

Is there a way to move the speed sensor, or do some other adjustment, to slow this one engine down?

As always, thanks - walt

Walt,

You say that they're "twins", however, were they manufactured at about the same time or is one a newer release than the other? If one is newer, then they could have different sound files and one may have a defect in its speed algorithms.

If they have the same sound file, then I'd suspect a difference in either the tach reader spacing, or a defective tach reader or timing stripes.

First, it would help to know which engine is actually off-speed, and if it's too fast or too slow. Learn this by comparing it to your other PS2 engines or against an O scale "measured mile".

If the problem engine is too fast and it has painted timing stripes, the paint may be too porous for the tach reader to get an accurate reading. In this case, covering the painted stripes with a timing tape may resolve the problem, as it did for me.

I don't think it makes a difference whether slower or faster loco is first, since they are effectively locked together. If there are noticeable speed differences, to me it is a recipe for eventual overheating trouble with the motors.

Walt,

I had that problem once with two identical engines. One was way faster than the other. I put them both in the "lubratorium", pulled the motors, greased all gears, oiled all shafts and axle bearings. After that treatment they were perfectly matched in speed.

Because of the way I run my trains (two triples, 10 doubles and 3 or 4 trains per loop simultaneously), this was an item of concern to me that I voiced to Jason and David. Jason looked into it and later responded that a delta speed adjustment was not possible at the TIU level and if ever implemented would have to occur within the engine hardware/software. I doubt that it if such a change will be made within my lifetime. What would be an easier fix would be to have the ability to adjust speed within 1/10 of a mile increments. I can dream. Any way as a pratical matter I had two engines (Rdg Alco S-2 and a V1000) that were off by a significant amount that I would start them with the other trains using the "All" command and then directly accessing the V1000 to its correct speed to match the Alco. That did work; however, I just got tired of this when having folks over to run trains and having them try to do those speed changes that I dumped the engine. With five Legacy engines, my experience is that their speed steps permit fine speed control (speed step 38 ~ 10 smph) and all their engines appear to have less speed variance than Proto 2 engines. I think MTH is missing the boat on this and have been passed my Lionel for those of us who run multiple engines simultaneously on the same track. As a side note, both Jon (Lionel CTO) and Sherman (Kline engineer) have told me that the slower engine should be the trailing engine. Jon went so far as to say that they change the speed of the lashup trailing engine so that it is slightly slower than the lead unit. Also Sherman indicated that if you had multiple cruise control engines in a consist and you could disable cruise, disable cruise in the trailing engines.

Both are RK Erie Lackawanna RS3 engines. One was bought NEW 4 years ago and the other bought NEW only 2 years ago but both have the same model number so to me they are the same.

The older one runs faster. BTW: my 5 to 8 SMPH comment is while running at only 30 SMPH. The discrepancy is worse the faster they run. The 'older' one runs faster than every other PS2 engine that I have by about the same variance.

I have lubed them as that is a routine that I do every year after getting them out of storage in prep for the Christmas layout.

I'll take the hood off and check the condition of the timing tape.

Barry, you hinted at an answer to my question by saying:

quote:

a difference in either the tach reader spacing

Does that mean that if the tape looks good then I can try adjusting the spacing between the reader and the timing tape??? I would guess minute movements make a huge difference so I'll be careful if you think moving it will help. Would I want to move it closer or further away to SLOW it down?

thanks - walt

Walt,

Your problem is identical to one I had a couple of years ago that was resolved by placing a timing tape over a painted flywheel of an engine that was too fast by about 15-20%. Another time, the same problem was the result of a tape that became saturated with smoke fluid and was "grayed out".

Don't fiddle with the tach reader spacing until you try check out all aspects of the timing stripes, unless comparison between the two engines shows hat the tach reader spacing is significantly different.

quote:

Originally posted by walt rapp:
...
Does that mean that if the tape looks good then I can try adjusting the spacing between the reader and the timing tape??? I would guess minute movements make a huge difference so I'll be careful if you think moving it will help. Would I want to move it closer or further away to SLOW it down?

thanks - walt

If an engine runs fast, it's generally because the tach reader is not sensing all the stripes; so the motor runs faster trying to compensate. As Barry suggests, carefully look at the flywheel for solid and un-faded bars. There is no simple answer to "closer or further," it could go either way depending on how the stripes are degraded. There is an optimal distance - too close and it won't work, too far and it won't work. If the striping is degraded, adjusting the gap distance is a two-wrongs-make-a-right proposition - better to replace the tape.

If the tape looks good, one long shot may be gunk got on one or both of the lenses of the black optical sensor on the tach reader facing the stripes. You should be able to slide a thin damp cloth into the gap and slide it back-and-forth across the sensor (not the flywheel).

It will be disappointing to me, in a way, if it is the tape. The engine has only been used for 4 years and then only for a short while during the Christmas layout season (about 3 months for me).

The engine does not have a smoke unit.

So if the tape goes bad that quickly with that little bit of usage, that's not saying much for the quality of how it's made.

But I'll look soon as I get a chance. I haven't lubed anything yet for this year's display so that will "force" me to check it out. If it looks even the slightest bit different than its twin (which runs about the same speed as my other PS2 engines) then I'll ask MTH to send me a new one.

Thanks for your suggestions! - walt

Walt,

The early PS2 engines made in 2000, used a paper tape on the flywheel that didn't hold up and came apart. New tapes are made of better material ( vinyl I believe ) and they will last much better.

Is yours a #30-2208-1 ? This is an early model.

Thanks Joe.

My memory was playing some trickerations on me and the engines are older than I stated. I just looked at some old layout photos and the "original" twin showed up for the first time on my 2002 Christmas layout (bought engine at April York though).

I was right on its younger twin: it only showed up on the layout in 2007, but I know for sure that it had the same model number as the 2002 one. I remember at York asking the vendor if I could take it to the MTH booth to confirm that it was identical to the one that I already owned. Andy looked up some info and confirmed the match.

quote:

#30-2208-1

I'll check when I get home tonight.

Can't wait to get to that timing tape! Maybe I should take a break from wiring and open 'er up tonight.

- walt

you were right Joe, it is the 30-2208-1. Haven't opened it up yet though.

If anyone checks back here, I'd like to ask one more question: If the black stripes seemed to be NOT real dark, is there a temp fix like painting or using a black pen or marker??? I only have a Christmas layout so I need the FASTEST way to get it corrected.

thanks - walt

Ron of Engine House painted the stripes on my Kline Tank engine when he did the proto 2 conversion (the flywheel was too thin). As a result I would try the magic marker; however, unless you are getting surges in speed for one revolution, I do not think that is your issue. For me the ideal situation would be to have the capability via a parameter entered into the sound file before it was downloaded to the engine that would modify the algorithm associated with the computation of a single revolution. This Christmas while I am burning up use of lose leave I might see if I can decompile (reverse engineer) the sound file to identify the value that if I can change by an incremental percentage to permit a better match to scale mile per hour. If I can find it it would be an easier method than pulling shells and taking guesses on modification of flywheel stripes.

quote:

however, unless you are getting surges in speed for one revolution, I do not think that is your issue

No surges, just run faster than all my other engines.

OK, I HAVE to make opening it up a priority at this point. Need a definite answer on the state of the tape.

thanks -walt

It's NOT the tape. It's solidly in place, it's clean, and the black lines are very black. I don't know if I should be happy or disappointed!

It's well lubed.

I was hesitant to play with the spacing between the reader and the tape so I didn't. Maybe when I get its twin out to lube it I can compare. I'm feeling though that even if there is a difference it will be so small that eyes won't detect it.

I either find a solution or kiss my lashup goodbye, which also means keeping one of the engines in the box and not using it.

thanks for the suggestions though - walt

Walt,

Are you saying that both engines are #30-2208-1, cab #930? In that case, both have timing tapes (rather than painted flywheels) and, if the faster engine's tape looks good, there are really only two possible reasons that one is faster than the other:
• The tach reader on one is defective or not properly spaced from the flywheel.
• The sound files are different and one has a bug in its speed algorithms (it wouldn't be the first time).

If, however, they are not identical engines, there are only one or two other possible culprits.

Thanks for checking back in Barry.

Yes, I confirmed last night that they are the same model number and same cab number.

I compared the spacing of the 2 readers and both SEEM to be the same.

Both tapes are in good shape.

Both play the same station sounds and stuff so I would say that they have the same sound file too.

I guess my last comment then is..... RATS!!!!!

I don't dare run them as a lashup knowing the speed differential and risking ruining one or the other. One sits

Thanks for the suggestions all and trying to help - walt

Walt,

quote:

Both play the same station sounds and stuff so I would say that they have the same sound file too.

I would expect them both to have the same (freight yard rather than passenger station, I would think) sounds even if the sound files are different. The only difference would be that one sound file has defective speed algorithms and the other's speed algorithms are correct.

If you can your TIU to a PC, you could then do one of the following:
• Upload the sound file from the good engine (that runs at or close to the speed of your other PS2 engines) to the PC and then download it into the other, faster, engine.
• Download the latest sound file for the engine from MTH's web site and download it into both engines.

If you like, I could E-mail you freight yard sounds from a Rail King NYC RS-3. Let me know.

That's a terrific suggestion!

Sadly, getting to my TIU at this time is another matter though. Depending on how badly I want to use the lashup on this year's Christmas layout I could get to it if I really HAD to (only the external fast blow fuses are easily gotten to right now). One of the pitfalls of having a floor layout and trying to hide as much as possible.

If nothing else, I will print the suggestion on the using the same sound file in both and try it when I'm tearing the layout down. Always next year!

thanks again - walt

quote:

Sadly, getting to my TIU at this time is another matter though. Depending on how badly I want to use the lashup on this year's Christmas layout I could get to it if I really HAD to (only the external fast blow fuses are easily gotten to right now). One of the pitfalls of having a floor layout and trying to hide as much as possible.

If nothing else, I will print the suggestion on the using the same sound file in both and try it when I'm tearing the layout down. Always next year! Smile

You must have the layout set up already Walt , great! Did you order one set or 2 sets of timing tapes. Wouldn't you have to replace the tape on both engines? Don't rule out the spacing on the reader and timing tape, it does make a difference, don't feel too bad, we have 3 identical RS-3 , that all ran at different speeds.

quote:

we have 3 identical RS-3 , that all ran at different speeds.

Gregg,

So did you get them to eventually run the same speed someway? If so, would you share what you did?

I didn't order a tape yet thinking that I probably won't get it in time to use and the existing ones seem to be in excellent condition. I want to try Barry's suggestion on the sound file too.

thanks - walt

Hi Walt, Seems I adjusted the spacing between the timing tape and reader with either plastic wire ties or tooth picks to force the reader one way or the other. I would never try soldering a spacer to the reader.

The engines are still not perfect but at least I can run them as a lash-up without them fighting each other and over heating.

I don't know what else you can try? You would think if 2 identical engines had the same timing tape and sound file they would run about the same speed.

Good luck.

Thanks for answering Gregg.

I visually compared the spacing on both engines and to my eyes I can't tell if they're different or not. That being the case, one would think that if the spacing is that similar it shouldn't matter. But then, what do I know?

thanks - walt