Need Help with PS2 Roller Modification

First off, unless you have a pretty wide space where there's no power, the double rollers are going to be better than a single roller.  I don't see any easy way to space them wider in that truck anyway.

 

A likely scenario may be that the 2-rail/3-rail switch is defective or there's a problem in that wiring.  That would isolate one side and with traction tires, you'd only have two wheels on track common.  That's probably more likely to be the issue than the rollers.

 

I'd check the continuity between sides on a single axle, you should get zero ohms or close to that on each axle.  If there's no connection there, fix that and leave the rollers alone.

 

I did the continuity check with the Fluke and got the "beep" when connected across a single wheel pair and an indication of about 7 ohms. Note that my intent is to have two rollers per truck (4 total) by finding a way to add a second roller for each truck toward the left side of the photo. To do that though I have to remove some pieces. Then see if it's possible or not.

 

I take it that this 2R to 3R toggle design was not hugely successful.

 

Thanks, S

Scott,

Did you grab the manual? Anyway, here it is.

 

This engine has more switches- there's a polarity switch as well as the 2R-3R switch.

 

If the track switch tracks are back to back, is there any reason you can't put a power drop (hot and common) on one them to shorten the spacing?

 

EDIT: Link to Atlas switch jumpers to power rails:

https://ogrforum.ogaugerr.com/t...las-switch-problem-1

 

While you have the meter on the wheels of one axle, does moving the 2R/3R switch change anything?

Wheel cleanliness matters, so making sure you have a good ground and good center rail pick up is  important.

 

The 2R-3R is a successful design and many steam and diesels have it and work fine.

 

I have yet to run into a faulty switch, but I am sure some have.

 

If this is truly a spacing of the roller issue on your layout, all the modification to the engine isn't going to do anything.  I don't see how you can change the pickup rollers spacing on a 4 wheel truck.

 

Modifying your layout is required or stay away from the small spacing engines.

 

An alternative is a dummy engine with pickups and a tether between units to transfer AC power into the lead unit.

 

What I would do is look at where the engine stops and see if it should still have power.  If so, check the track pieces for proper continuity, and check the engine.  I have seen the dirty wheels, corrosion inside a roller, black coated terminal screws that don't conduct, damaged wire, as the main culprits to continuity issues. 

 

When in the 3R position, both outer wheels should be connected via wiring through the switch.  If not, that could be an issue.  You can't really gut the switch unless you just want to hardwire the axles, but if the switch is working why go to that effort.   G

I have a MTH PS2 WM BL-2 (not 2-rail) and have no problems whatsoever. 

 

I think GRJ may be on the right track when he says to check ground.  Try connecting a jumper in the loco between right and left side wheels.  An alternative, when loco is stalled, take a jumper wire with one end connected to outside rail and touch other end to loco frame.

All,

 

Many thanks. Just the kind of feedback I was hoping for. Here's what I've learned and know for sure.

 

1) In 3R position I get continuity between common wheels on the same truck. In 2R switch position it reads open. I don't think there's any problem with the switch.

2) Where the engine has quit and lost power I have tilted it up and sure enough, one roller pair is on the dead rail only and the other is just barely making contact with the forward hot rail. That said there have been times when the engine has crossed OTHER similar spots with no problem. But now it quits on those same spots.

3) The wheels and rollers are free of any debris or build-up that would degrade contact.

4) I did do a full factory reset.

5) I did change the battery and the engine behaves correctly on power down.

 

Last night I removed the plastic top piece (insulator) and found a bunch of lubricant (oil) between the insulator and the truck block and also under the roller base and am in the process of cleaning that up.

 

Will report back on whether or not the cleanup helps.

 

Thanks again.

 

S

the other is just barely making contact with the forward hot rail.

 

When loco is in that position, reach under it with a tiny screwdriver and touch roller and center rail.  If it doesn't cause loco to light up, issue is ground.

Gentlemen,

   I am with GGG on this one, more than likely layout modification will need to happen to fully cure his problem, or the addition of the dummy power drop with tether.

PCRR/Dave

As I said, I have that loco and have no problems.  Before doing anything, you have to find out if it's losing ground or hot.

Scott, if you're never going to run it on 2-rail track, why not make a permanent, internal connection between the wheels on both left- and right-sides?  If you're running it on traditional tubular track this happens by default.  It certainly couldn't hurt.  My $.02.  -Ted

I have seen a bad 3R-2R switch, and that's a very flimsy looking switch they use, so I'd make sure it's the wheels and not the center track pickups.  It's really hard for me to imagine that two sets of double rollers are all missing live tracks, that has to be one very unlucky happening.

 

I'm on travel now. I did check again and the rollers are just unfortunately spaced. There are others issues, however, that can't be explained by just roller spacing. In one case the engine got to where the forward rollers came to an uncoupling track section and somehow shorted the track and tripped the breaker for the layout. Go figure. When I get back I'm going to add a booster roller under the fuel tank and see what that does. In the end I would prefer to disable the 2R option as suggested above.

Thanks for all the feedback.

The Switches used are the same they have been using since the PS-1 days.  This is the wider large switch not the thin versions like Lionel.

 

One failure doesn't make the switch flimsy looking.  IF you think it is, then all your engines with switches are flimsy.

 

The wiring of 2R-3R when in 3R position ties the wheels as one.  There are 1000's of 2R-3R engine running perfectly.  We only see issues every once in a while.  Mostly driven by pickup spacing.

 

Scott has confirmed good wheel continuity in a previous post, and he confirms the spacing is on a dead section of track.

 

I would confirm both rollers have continuity with an electric tape test.  G

IMO, they all are pretty flimsy, they are very cheap switches.  The issue with all of them, Lionel and MTH is that if there's any pressure applied to the switch handle, it can bend the small tabs and compromise the switch.  That's happened to several Lionel ones as well, and I've had to crimp those switches on a couple of new items, apparently from shipping handling, the trucks push on the switch in a drop and bend the tabs on the rear.

 

The switch for reversing is a wider switch, but it's also a DPDT switch, so it had to be wider.  If you open one up, you'll find the contacts are the same size as the SPDT switches commonly used in other positions and for Lionel stuff.

John,  I am over 1000 MTH engines repaired  Maybe twice that many.  I have yet to run into a broken MTH switch.  Sorry, your wrong.

 

Lionel yes.  I have had 2 or 3 switch that pressed out.

 

There would easily be hundreds of post about MTH switches if there was a problem.  I can only remember 2 or 3 post about the 2R switch.  Usually a broken solder joint, and I think Barry posted about one engine that did not have both outer wheels connected when in 3R.

 

Center rail roller spacing on smaller enignes.  Yes, that can be an issue on some track switch types.   G

 

 

So, the fact that you haven't seen one and I have makes me wrong?  Interesting way of looking at the world.

 

John Yes,  seeing one in thousands is not a problem.  You call it flimsy because it is not to your standard (what ever that standard is), yet from what we see the failure rate is significantly low.  You only saw one.  Every PS-1 and early PS-2 had switches.  Every 2R-3R has multiple switch.  Yet 1 failure reported?

 

This is a toy, not an aircraft safety switch.  By declaring it a bad thing with a negative adjective you can have folks wasting time chasing ghost.

 

But hey, change them all out if you think they are substandard for your engines.  From what I have seen they work well enough for a toy train.   G

Well, I still feel they're a pretty flimsy switch design, but your point about the observed failure rate is valid.  I only saw one, and I don't know exactly what happened to cause it to come apart, could be user abuse.

 

I'd change them, but I don't know what else would fit in the hole.

 

I had two different customers one right after another where the copper in the switch got bent and wasn't making contact. They both weren't going to use it and had no intentions of selling it so I just bypassed it for them.

The thing that's funny is they were both NS SD-70's.

Ralph, that can't be, those switches never fail.

 

OK guys.

 

I don't have any of the 2/3 locos.  How is power picked up from the wheels on each side? 

In one case the engine got to where the forward rollers came to an uncoupling track section and somehow shorted the track and tripped the breaker for the layout.

 

Scott, I had this happen once many years ago.  I forget if the roller was canted, or just a very wide roller.  It touched one of the control rails that was connected to ground and caused a short.

Ok we are up to 4 world wide  G

Well....electrons flow through metal track into metal wheel into metal bearing with brush attached.  Plastic insert  isolates wheels. 

 

Right wheel is equivalent to center rail pickup when in 2R position.  It connects to tender board via black wire in tether.

 

Left wheel is chassis ground and connects to tender via draw bar.

 

When in 3R position right wheel becomes connected to left wheel via wired switch in tender.  G

Scott,

 

Make sure it is not a ground issue.  You can test this by holding a jumper wire on your outside rails in the offending areas on your layout.  If you are using switches that are not wired like the Ross-Ready, this might be your problem.

 

If you do determine this it IS the issue, You can remove the bottom plate of the tuck (4 screws and pickup roller) and swap the two wheel sets.  This will change your ground spacing.  It is pretty easy to do.

 

I understand why MTH developed the 2/3 truck/system but I am not a fan. Especially in steam engines.  It can cause issues on some layouts and non-derailing features if everything is not 100%

 

BTW I have also seen 2 switch failures bringing us up to 6 worldwide  I usually hard wire my personal engines to 3 rail DCS.

 

I hope this helps and wish you the best of luck.

 

Dave

 

One more thing if you do this mod:

 

Take some emery cloth and remove the black from the wheels and flanges.

 

Dave

 

Thanks, GGG.  I assume that more than one wheel has this pickup.  If one or more of the brushes is not making good contact, could not that be the source of the problem?

Maybe but the engine drive wheels, rear pilot all feed the ground.  Normally both tender trucks also feed ground.

 

So how many points of contact do you want?  G

 

Dave, can you explain what swap you are doing?  Is this for Steam? or Diesel? or both? 

 

6 out of 600,000?  Poor batting average  G

One issue is for folks that use one rail for signals and not power, in one direction all those wheels on one side are not receiving power.  If there's a flaky or non-existent connection to the other side's wheels, there's be trouble.

 

As far as the bad switches George, have you really seen the 599,994 good ones?  I think you're computations are a bit skewed.

 

Yep,  The problem seems to be more prevalent in steam engines.  Cleaning the wheels with a wire brush really helps.

 

Dave

 

John, Why would one rail on the whole layout be used for signals?  I got it on certain sections, but your still missing the point.  All the left wheels including trailing truck are grounds.  So a bad brush on one drive wheel should not be an issue as RJR asked.  Smaller engines sure.

 

Won't let go of the switch huh!  While this web is not a statistically accurate sample, it does gives a pretty good pulse of what goes on.  I was just assuming something over 600000 2R-3R engine made over the years, and the six reported switch found.  So lets make it 100 switches and 100,000 engines.  Still not a good batting average to issue a recall on switches.

 

Dave Yes steam are more of an issue because you don't have a 2R switch on the engine. So it relies on the draw bar as one wire.

 

Can you explain the truck swap you mentioned better?  G

 

 

Geoage,

 

You can swap the axles.  This would change the spacing on the ground pickup.  In some cases,this might help in the same way that changing the roller spacing would.

 

Dave

 

 

I'd lean towards the missing common due to the 2 axle's with rubber tires leaving you only 4 wheels for contact. Easy test is where it stalls jump a wheel flange with a wire from a good common rail. Betting that is the issue, have seen it a lot.

(For example an 0-6-0 may have no wheel to metal rail contact on a Ross 11 degree crossover.)

Having returned from travel last night I set myself to the task of adding a booster roller under the fuel tank housing as a possible solution. The results were a hole in the fuel tank/speaker casting and the realization that I did not think this solution through very well. Basically the engine came to rest on the roller I added under the tank leaving the front truck suspended in mid air above the track.

 

Although I don't have pictures to show, when the engine gets to track section where I have back-to-back 054 Atlas switches all 4 rollers end up parked squarely on the isolated rails and just out of reach of the nearest hot rail, maybe 0.05 inches away if that. There is at least one other section on the layout where this happens. Basically just bad luck. I have had this happen only once before but was able to re-space the rollers. So far I cannot find a way to do that with this engine. There is just no room within the plastic recess where the rollers are mounted.

 

Next up is to at least do what GGG recommended and add a trailing dummy engine with a third pickup off of that.

 

Man, this is frustrating.

I suspect putting a roller in the middle was doomed to failure from the start.   When you go around a curve, the center of the locomotive is nowhere close to the middle rail!

 

I take it you mean on the tender moving one side fwd or aft?

 

If the engine has good ground and the tender has good ground, the spacing is quite long and I would find it interesting if a track gap was the issue.  Seems to me the Achilles heal is the short center rail pickup gap.

 

Now if the ground isn't good all bets off.

 

When working these issues I take both shells off and connect draw bar and place on test track unpowered. I do continuity checks between 7 pin Red and Black and the rails.  I then remove engine and test from 7 pin to each roller and each wheels set making sure I have power conductivity with near zero resistance.  You can flip the 2R-3R and repeat.   G

 

This may be too simple or I missed something, is it possible to use two separate rollers inside the truck shown, and move the rear roller (looking at this picture, the left one) back (to the left) as much as possible, do same for the other truck. This will be more than the 0.05" gap problem area you mentioned...

 

Else, run the train very fast and its momentum will carry it through the dead spot

I think George's suggestion of a single-wire tether to a trailing car will probably work best.  It looks pretty hard to fit a wider set of rollers in those trucks.

 

If there's clearance behind the truck, you might be able to graft a roller on the inside of the truck that would alter the spacing enough, but I suspect that's probably not possible due to the fuel tank being there.

 

Do you have a shot of the whole underside?

Maybe but the engine drive wheels, rear pilot all feed the ground.  Normally both tender trucks also feed ground.

 

So how many points of contact do you want?

GGG, when shipped, the Imperial Decapod had 24 theoretical points of contact.  Yet it would stall due to lack of ground when going over non-derailing switches, under certain circumstances.   BB eventually also found this problem.  In part, the blackened screws being used may insulate, bit in any event trucks apparently no longer can be assumed to provide ground without a wire & wiper for electrical connection.  Drivers also cannot be relied on