Having trouble getting two identical Lionel powered B units to run at the same speed. Any ideas on what the problem might be?

If 2 motors in the B units confirm that both motors in the new B unit are working.

Was the B unit new or used? If it was used check to make sure the momentum is the same as your A-B units. You might also try setting the stall on all 3 units.

Doug

If a motor was dead, that truck's wheels would not turn.

How large is the speed differential? No two machines, real or model, are exactly the same, and this can show up in a speed difference. If it is small and the MU'd locos act normal, it can be ignored. 

How do cumulative run times compare between the new (to you) and old units, so far as you know? The new one may need some run-in.

Not having any Legacy diesels I do not know this, hence my question as I only have Legacy steamers.  On many Legacy steamers you can pick up the locomotive and move the wheels by hand.  Can you do this with these locomotives?  If so then I wouldn't worry about speed differences (Small ones.) as the transmissions can take up the differences like they do on Legacy steam.

Hook'm up & go. You will never notice, and it doesn't matter.

I have F3 TMCC units from the same era. You say the SKU of the B units is the same, in which case, assuming they are identical, I'd expect any speed difference to be really so marginal that you would not notice it once all the units are running together. You should check the momentum setting of each unit or rather reset all of them to the same setting.

However, I found that in fact Lionel produced a batch of F3 B units a year or so apart - so different SKUs - where the gearing was different and a substantial speed difference resulted. I could see one of my B units effectively being dragged along by the other A and B units in front. 

There was no remedy for this as the problem was the hardware being different. The symptoms you describe sound a lot like mine - are you sure your B units are identical?

These are Odyssey engines. Make sure Odyssey is turned on for all of them. Some of the early Odyssey diesels had a switch to turn Odyssey on and off. If it doesn't have a switch there is set of keystrokes that does the same thing. Check you manuals.

I run a Train 18 B unit with Train 19 powered A and powered B units no problem.

If you try and run with Odyssey off startup will be all over the map. Some will start at 2 or 3 steps, others won't start until 7 or 8.

Pete

Hancock is right on. I'm guessing because of the time at which you purchased them that these units have Odyssey I, without an on/off switch. If this is so, you won't be able to run them together unless they are from the exact same, or very close release date. The only other thing I would make sure of is that all of their momentum settings are off (L button on the TMCC/Legacy remote). If that doesn't work you might be SOL.

Try running them conventionally as well.

ADCX Rob posted:

Hook'm up & go. You will never notice, and it doesn't matter.

Absolutely 100% correct.

MU’d locomotives do NOT have to run at the exact same speed when tested independently. A “faster” locomotive will pull on the train a bit harder than a “slower” loco, but as long as there are no wheels sliding, you’re cleared to the main!

Your original A & B units have been run a good bit more than your new one so it may loosen up given some run time however once all the electronics are in the same state, stall  and momentum,  you may think about examining the grease in the gear boxes. One more check is to put a sharpie mark on the flywheels and on a wheel on each truck, turn the flywheel by hand and count the turns to make sure new and old are geared the same. With the same sku I would not suspect this but you never know.    j

This has been a known issue, with no resolution . I have the WP, UP, PRR,  and SF in TMCC and they all do it. Still don't know the fix. And the speed is ok in some steps, and worse in others.  Especially at higher speeds 

Thanks for all the great suggestions. I will try them all this week and let you know the results.

John

I had a chance to look into your suggestions last night. Here is what I did;

• verified that all wheels are turning when power is applied. This would suggest that all motors are working.
• wheels cannot be turned when there is no power
• Made sure Odyssey is on in all units using the Cab-1. By the way, there are no Odyssey On/Off switches on any of these units even though it says there is in the manual.
• Reset Momentum to L on all units.

Now the two B units appear to be in sync with each other, however, now the A units pulls away from the 2 B's.

Here are two videos. The first one is at a very slow startup speed. The second at a higher speed. As you can see, the A unit runs away from the other two.

I know some have said not to worry about this but I just want to be sure I don't do any damage to any of the units by running them together.

https://www.youtube.com/watch?v=jYnI4fPTtvI

https://www.youtube.com/watch?v=3AJ6EMs6yb0

Thanks

John

J Daddy posted:

This has been a known issue, with no resolution . I have the WP, UP, PRR,  and SF in TMCC and they all do it. Still don't know the fix. And the speed is ok in some steps, and worse in others.  Especially at higher speeds 

Watched an A-B-A set of the Lionel UP TMCC F units run at a guys house. Asked him if the B unit on the shelf was a dummy. He said "no, it is the powered and always causes issues."

Pulled it down and added it to the others for an A-B-B-A set where sure enough the speed difference was so great he had to remove it.

Unless someone already stated....in order to run the engines, don't they all have to be programmed/given the same engine number...? I'd also agree with whomever said to check that both motors in the recently acquired B UNIT are operating. Good luck on the possible repair.

redjimmy1955 posted:

Unless someone already stated....in order to run the engines, don't they all have to be programmed/given the same engine number...? I'd also agree with whomever said to check that both motors in the recently acquired B UNIT are operating. Good luck on the possible repair.

 

 , 

I have done everything above and more.

Programming them to the same number and/or creating a TR lash-up made no difference.

Greased the gears up, have run them with and w/o Odyssey, even swapped motor driver boards, pop the lids to verify motors and gears are not binding, checked and verified the motor gears are the same size and of the same year release... no change.

I suggest NOT running them together if they differ in speed. They will tear your track up, one will get hotter than the other, and you will lose traction tires.

I have not found a fix yet.

If the B units are slower than the A, just run em....just keep an eye on the temp of that A unit, feel the top of the shell after its been running awhile.

The worst mine ever did was rip the center idler gear out of the truck. If that does happen just run it with one powered axle.....doesnt make a difference.

What's the gear ratio of the A unit?  Is it the same as the B units??  The difference in speed isn't that great.  But the fact that both B-units run EXACTLY the same tells me there's definitely something different about the 'A.'

   Is there a flywheel tape being read?  Count the stripes, they would need to match numerically white= to white, black to black. A dirty tape or read lens can do that too if involved.

I guess I was just lucky. Mine all run together. The speed sensor involves a magnet. Dirt won't affect it. Gearing is the same for all the TMCC F units.

Lionel did make a change to their Odyssey DCDS board somewhere along the way. Likely this A unit is indeed different from the B.

One not so inexpensive fix would be to replace the DCDS motor drivers with ERR Cruise Ms. Those can be adjusted for any small differences in speed.

Pete

Norton posted:

I guess I was just lucky. Mine all run together. The speed sensor involves a magnet. Dirt won't affect it. Gearing is the same for all the TMCC F units.

Lionel did make a change to their Odyssey DCDS board somewhere along the way. Likely this A unit is indeed different from the B.

One not so inexpensive fix would be to replace the DCDS motor drivers with ERR Cruise Ms. Those can be adjusted for any small differences in speed.

Pete

Pete- yes for 100 dollars each you could upgrade, and for a time there I was buying B units for the same price. So I have quite a few extra B units as you can imagine. The worse offenders are the Santa Fe and UP F3 sets. Still have not found a match. I think these will be the ideal candidate for ERR boards.

OK, run your test again, but with the consist connected to the A unit, B units out front.

I have the first issue scale lionel Santa Fe f3 A A units #16 and would like to get a b unit for it.  I don’t think I need the pulling power from the b unit and would be happy with a non powered,  but I don’t think there was one made for the #16 set.  It seems like Lionel had a lot of random brochures back in the early 2000s for items not in their normal catalog.

In this search, I had concerns on color matching the silver and compatibility with different rev years of Odyssy from Lionel.   I posted this last week and for some reason it was deleted.  Hoping some one on this post may have some knowledge on this.  From this thread here, it sounds like speed matching is problem for all of the powered b units?

I was considering the #16 b unit (24526)or the #18 b units (24532 unpowered or powered 24533) from Lionel.  Any advice would be appreciate on this.

Allow me to repeat what I posted back on December 22, 2018…

MU’d locomotives do NOT have to run at the exact same speed when tested independently. A “faster” locomotive will pull on the train a bit harder than a “slower” loco, but as long as there are no wheels sliding, you’re cleared to the main!

@Hump Yard Mike posted:

From this thread here, it sounds like speed matching is problem for all of the powered b units?

It really depends on how much mis-match here is.  Very few engines are going to run perfectly with another with no variance in spacing.  If you have a huge speed difference, it's likely to be an issue.  If you have a 5% speed difference for instance, it's likely to be fine.

Interesting thread. After  tr18  reset of the A and B units, here is what was stated:

"Now the two B units appear to be in sync with each other, however, now the A units pulls away from the 2 B's."

Prior to this change, the original A and B unit worked fine together.  After the change was made, now the two B units match.  But the A unit no longer matches.  What would cause this?