Worm Drive (Triang) Chassis "Sticky" in Reverse

[PatB]

My small collection of Triang 0-6-0s are all running quite nicely, following cleaning and some selective assembly. However, something which seems to occur to a greateer or lesser extent with all of them is an occasional reluctance to start in reverse (ie, loco bunker first and chassis motor first). This is only slight, and probably wouldn't be noticed on a layout, but these do duty on a shop window display, requiring a direction change several hundred times a day, and so require a finger poke rather more often than is really acceptable in something that should run largely autonomously.

 

Power source is an Arduino motor shield, controlling speed by PWM. I've changed the Arduino PWM frequency to 30+ kHz to keep things quiet, but the issue manifests at the default frequency too, so I doubt if it's related. I've checked track connections, cleanliness etc. and can't find any problems. It does seem to be isolated to the loco but, as noted, all the locos seem to do it, some more than others.

 

Given that it seems direction specific, my suspicion is falling on the fairly crude worm drive and motor arrangement. Chassis with both brass and nylon gears appear affected, so I'm reluctant to ascribe it to gear design. I've been wondering if it's armature end-thrust related and whether it's a known problem with X04s with single-stage gearing. And, of course, whether there's a fix.

 

Any advice appreciated. I'm reluctant to give up on these chassis as they are otherwise ideal for this purpose, being cheap, user serviceable and with a good supply of spares.

[Nearholmer]

Excessive end-float in the X04 motor shaft, causing slight fouling between brushes and commutator end plates?

 

A very common cause of this problem, and it gradually gets worse.

[34theletterbetweenB&D]

4 hours ago, PatB said:

... And, of course, whether there's a fix. Any advice appreciated...

Endless maintenance is what these require. Part of the trouble you will have is that all the working mechanism parts are now worn, and what that does is accelerate wear on any 'new condition' parts you put on. This is what happens with all ageing machines and why eventually they get replaced.

 

If this is commercial use in a shop window, cost what the 'finger pokes' do to your business effectiveness, and the maintenance effort with those 'cheap' spares. Rational solution: sell them and use a modern multi-stage gear train drive model.

[Gordon A]

What sort of current is available to the track?

Have you checked the brushes and cleaned the commutator in the motors?

Clean wheels and clean track are a must.  I use WD40 Contact Cleaner these days as my general track and wheel cleaner.

 

Gordon A

[Graham456]

1 hour ago, Nearholmer said:

Excessive end-float in the X04 motor shaft, causing slight fouling between brushes and commutator end plates?

 

A very common cause of this problem, and it gradually gets worse.

 I second that as being the problem  only fix is to dismantle the XO4 and put a washer between the commutator and front end plate just like can be found on some XO4's from new  might be simpler to bung another  XO4 in though plenty of X04s around there not in short supply,

n b it's not a metal washer used as that would short out the commutator !

Edited October 22, 2019 by Graham456
Added n b

[PatB]

1 hour ago, Nearholmer said:

Excessive end-float in the X04 motor shaft, causing slight fouling between brushes and commutator end plates?

 

A very common cause of this problem, and it gradually gets worse.

 

I'd begun to suspect something like this, as the problem manifests when the armature would be pushed in a direction that would encourage it.

 

28 minutes ago, 34theletterbetweenB&D said:

Endless maintenance is what these require. Part of the trouble you will have is that all the working mechanism parts are now worn, and what that does is accelerate wear on any 'new condition' parts you put on. This is what happens with all ageing machines and why eventually they get replaced.

 

If this is commercial use in a shop window, cost what the 'finger pokes' do to your business effectiveness, and the maintenance effort with those 'cheap' spares. Rational solution: sell them and use a modern multi-stage gear train drive model.

 

I'd describe the window display as more a bit of fun than anything with serious commercial value, hence my reluctance (and, frankly, inability) to spend more on it. Maintenance, however, isn't too much of a problem as I can fiddle with stuff during quiet times in the shop.

 

21 minutes ago, Gordon A said:

What sort of current is available to the track?

Have you checked the brushes and cleaned the commutator in the motors?

Clean wheels and clean track are a must.  I use WD40 Contact Cleaner these days as my general track and wheel cleaner.

 

Gordon A

 

The motor shield I'm using has a rated output of 0.5A. On test, the loco, running light, pulls about half that. In operation, though, it hauls a pair of heavy Dublo Weltrols, so I might stick a meter on it to see if it's exceeding 0.5A under load.

 

7 minutes ago, Graham456 said:

 I second that as being the problem  only fix is to dismantle the XO4 and put a washer between the commutator and front end plate just like can be found on some XO4's from new  might be simpler to bung another  XO4 in though plenty of X04s around there not in short supply,

n b it's not a metal washer used as that would short out the commutator !

 

Looks as if I'll be learning to rebuild X04s then. Any advice on what to use/where to put the keeper when I take the magnet out?

[Graham456]

10 minutes ago, PatB said:

 

Looks as if I'll be learning to rebuild X04s then. Any advice on what to use/where to put the keeper when I take the magnet out

 Well you don't need to tackle that end, once you have taken the motor out, remove the worm with puller or such like. Then the fun bit as you have to remove the brass end plate by undoing the crimps to fit a fiber washer on the end of the shaft before reassembling I won't describe how I did that as their must be a better way (less crude)

[Nearholmer]

If it is excessive end-float, you can sometimes make a quick "get you home" bodge by making a brass clip/strap to go round the end of the motor, so that the shaft-end bears on that. You can test for the problem by gently holding a screwdriver tip on the shaft-end as you bench test, although it is driven by the torque at the gear, so sometimes doesn't show up until under true load.

 

Graham is "bang on' with the proper fix.

 

Its years since I did one, but IIRC the easiest way to undo the crimps is by levering open a bit with a jeweller's screwdriver, then using very fine nose pliers,

Edited October 22, 2019 by Nearholmer

[RobjUK]

3 hours ago, PatB said:

Any advice on what to use/where to put the keeper when I take the magnet out?

If you want to be safe, just put a bit of reasonably thick flat steel against either side of the magnet itself, so they bridge the top and bottom plates.

That will provide a decent magnetic circuit if you do need to remove the armature from the polepieces.

 

 

[PatB]

3 hours ago, Graham456 said:

 Well you don't need to tackle that end, once you have taken the motor out, remove the worm with puller or such like. Then the fun bit as you have to remove the brass end plate by undoing the crimps to fit a fiber washer on the end of the shaft before reassembling I won't describe how I did that as their must be a better way (less crude)

 

3 hours ago, Nearholmer said:

If it is excessive end-float, you can sometimes make a quick "get you home" bodge by making a brass clip/strap to go round the end of the motor, so that the shaft-end bears on that. You can test for the problem by gently holding a screwdriver tip on the shaft-end as you bench test, although it is driven by the torque at the gear, so sometimes doesn't show up until under true load.

 

Graham is "bang on' with the proper fix.

 

Its years since I did one, but IIRC the easiest way to undo the crimps is by levering open a bit with a jeweller's screwdriver, then using very fine nose pliers,

Looks like my next spare time project is fabricating a worm puller then .

 

I asked about the magnet as, to the Mk1 eyeball (also a bit worn out in my case), it looked as though it would be possible to dismantle the motor from the rear without undoing any crimps, and pull the armature out from the back once the worm was off. However, I defer to those who've actually done the job and will have a go at the front plate. Meanwhile, I'll have a play with feeler gauges and micrometer to see how much play there might be, and what suitably insulating slippery stuff I might have that can be pressed into service for thrust washers. The plastic from 2l milk containers feels like it may make a decent bearing, as long as it's roughly the right thickness. 

[PatB]

As a matter of interest, the original test mule for the display was a Hornby J52, packed with as much lead as would fit in an effort to make its sprung trailing axle behave. In spite of Hornby's instructions suggesting a 50 hour motor life before the unreplaceable brushes wear out, it ran reliably for ~300 hours and, even now, I suspect just needs the carbon gunk hosing out of the motor. I have to admit I'm quite impressed, given the opprobrium often heaped upon these chassis. 

[RedgateModels]

Holy mother of God don't try to remove the brass end plate. Here's how I used to remove the magnet safely:

1. place a spare motor frame salvaged from a blown motor on a steel plate (an old triang tender weight works well) 
2. remove the motor retaining screw and place motor on top of spare frame. 
3. carefully slide the magnet down into the spare frame
4. reverse the process to get the magnet back into the good motor frame

This worked for me for years until I got a magnetizer. I just zap the motor as a matter of course now once reassembled...

 

Having said all this the motors come with a thrust bearing either side of the bearing in the brass front plate so should not need any other collar or shim. Just make sure that the worm is pressed on until you have negligible end float and the armature is free to spin.

 

Finally, make sure the brushes are not worn. Inability to self start can be down to the brushes being excessively curved around the commutator, this allows the brush to bridge the gaps in the commutator too much so the motor needs a good "kick" of current to overcome.

 

http://redgatemodels.co.uk/?page_id=100

[kevinlms]

1 hour ago, PatB said:

 

Looks like my next spare time project is fabricating a worm puller then .

 

I asked about the magnet as, to the Mk1 eyeball (also a bit worn out in my case), it looked as though it would be possible to dismantle the motor from the rear without undoing any crimps, and pull the armature out from the back once the worm was off. However, I defer to those who've actually done the job and will have a go at the front plate. Meanwhile, I'll have a play with feeler gauges and micrometer to see how much play there might be, and what suitably insulating slippery stuff I might have that can be pressed into service for thrust washers. The plastic from 2l milk containers feels like it may make a decent bearing, as long as it's roughly the right thickness. 

An idea, with some fibre washers, try cutting a segment out of the washers, in such a way that they can be force pushed onto the shaft, but tight enough that they can't fall out again. The same principle as a circlip.

 

Note, I haven't tried this and depending on the thickness, you might need multiple fibre washers. A bit of experimentation will probably be required. You should be able to do this without dismantling the magnet.

[PatB]

2 minutes ago, RedgateModels said:

Holy mother of God don't try to remove the brass end plate. Here's how I used to remove the magnet safely:

1. place a spare motor frame salvaged from a blown motor on a steel plate (an old triang tender weight works well) 
2. remove the motor retaining screw and place motor on top of spare frame. 
3. carefully slide the magnet down into the spare frame
4. reverse the process to get the magnet back into the good motor frame

This worked for me for years until I got a magnetizer. I just zap the motor as a matter of course now once reassembled...

 

Having said all this the motors come with a thrust bearing either side of the bearing in the brass front plate so should not need any other collar or shim. Just make sure that the worm is pressed on until you have negligible end float and the armature is free to spin.

 

Finally, make sure the brushes are not worn. Inability to self start can be down to the brushes being excessively curved around the commutator, this allows the brush to bridge the gaps in the commutator too much so the motor needs a good "kick" of current to overcome.

 

http://redgatemodels.co.uk/?page_id=100

That all makes sense. Thanks. 

 

The brushes on all my motors are used, and so have a decent arc to the contact faces. They have plenty of meat on them but may be acting as you describe. I'll check. 

 

There's definitely a bit of end float on all the armatures. Certainly more than I would expect in, eg, a healthy Dublo vertical motor. I'll have a good look and see if the original thrust washers are still in place. 

[RedgateModels]

3 minutes ago, PatB said:

I'll have a good look and see if the original thrust washers are still in place. 

 

Look at the pic on my website, one thrust washer is shown behind the worm gear, they are like "Top Hat" bearings and the larger face should be next to the main bearing both sides.

 

A bit of play is OK and the motors were assembled like this in the first place. It helps with a poorly meshing work and gear allowing the armature to float forwards and backwards if needed.

[Nearholmer]

"Holy mother of God don't try to remove the brass end plate"

 

She must have been on my side, because I certainly used to do that, and reassemble them, and they worked better afterwards.

 

The luck of the naive, I suppose, given that I started doing it when I was about ten years old and could get a non-working Triang Jinty at a Jumble Sale for pennies!

[PatB]

10 minutes ago, Nearholmer said:

"Holy mother of God don't try to remove the brass end plate"

 

She must have been on my side, because I certainly used to do that, and reassemble them, and they worked better afterwards.

 

The luck of the naive, I suppose, given that I started doing it when I was about ten years old and could get a non-working Triang Jinty at a Jumble Sale for pennies!

You clearly had a better class of jumble sales than the ones I remember. 

[kevinlms]

1 minute ago, PatB said:

You clearly had a better class of jumble sales than the ones I remember. 

The model trains I remember seeing at such places, usually consisted of the plastic Tyco and similar rubbish.

[Nearholmer]

This is well OT, but jumble sales provided: Triang Princess Elizabeth; many Triang "cast chassis" wagons and coaches; several Jinties; a Farish Q class; an HD 2-rail R1 (that one wasn't pennies); a rake of Triang Transcontinental coaches; lots of track; loads of Lone Star Treblo; most of our clothes and shoes; oodles of good books, a few of which I still have; etc. 

 

This was during the 1960s, and the Triang stuff was always 10+ years old, so often banana-shaped, and the locos were always broken and non-working, which is how I served my pre-apprenticeship in dismantling lots of things, and fixing about a third of them. I got the whole idea from my Dad, who used to buy non-working valve TVs on the same basis. Our house was littered with bits of dismantled TVs, as well as trains!

[Graham456]

4 hours ago, Nearholmer said:

"Holy mother of God don't try to remove the brass end plate"

 

She must have been on my side, because I certainly used to do that, and reassemble them, and they worked better afterwards.

 

The luck of the naive, I suppose, given that I started doing it when I was about ten years old and could get a non-working Triang Jinty at a Jumble Sale for pennies!

And on mine thirty years on from my youthful  doing it wrong. the ones I committed this crime on still run fine, and because it did it wrong and I didn't disturb the magnetic field by removing the armature from the pole pieces no remagatiseing was need pretty important if you don't have a remagntizer, but if you do have one going in the back way is simpler !

[hayfield]

Just to throw a spanner in the works, at one time several companies produced either direct replacement motors or motor conversion units

 

I am not advocating abandoning the chassis but if there is an option to upgrade the motor to one which will improve (rather than maintain) the locos performance

 

Whilst things like the ECM direct replacement motors were disliked, the MW/MRRC 005's still are very popular and available

 

An alternative is available from Southeastern Finecast where they do a motor mount for the Anchoridge motors (D11/12?)

 

Or may be someone has an idea on how to fit one of the newer reasonably priced can motors

[DCB]

I have several X04 motored locos in front line service and failure to re start when reversing is not unusual in a loco which otherwise works well.  Part of the problem is brushes  see below.  A partial cure is getting a Relco.  But a lot of the problem is production tolerances, some worm and worm wheel combinations work well, some don't. I have had to change one good X04 for another when the meshing is poor.   However the mod which works for me is shimming the worm wheel between the frames to reduce side play.  It means popping the wheels off, tapping out the axle and selecting suitable washers from your scrap box. I go for about 5 thou clearance,  With excess play the motor first pushes the wheel sideways before the play is taken up and only then starts to turn the wheel.   Usually the wheels bearing on the chassis control side play but bushes wear and often we need to widen the Back to Back for modern track which makes the issue worse.

The plastic gear has a nice recess which takes washers snugly so the washer turns with the gear. Controlling the armature end float (see posts above)  is also important.

Brushes need to bear on the sides of the commutator on the centre line of the armature, some are too long and when they wear they wrap around below the centre line which causes issues. A badly fitted insulating sleeve or connector tag can reduce brush tension on one side and this will hurt power and starting, usually in only one direction oddly enough.

The 5 pole motor Airfix MRRC X04 clone is generally a better starter than the 3 pole X04 but gutless.  My 94XX with 5 pole motor and Triang Jinty Chassis with Romford wheels but standard gearing runs nearly as quietly as a Bachmann 57XX and much more reliably being able to cope much better with really filthy track.

[uax6]

On ‎22‎/‎10‎/‎2019 at 09:36, Gordon A said:

What sort of current is available to the track?

Have you checked the brushes and cleaned the commutator in the motors?

Clean wheels and clean track are a must.  I use WD40 Contact Cleaner these days as my general track and wheel cleaner.

 

Gordon A

 

 

WD40 should not be used on anything that contains plastics as it degrades them. If not sure if the WD40 contact cleaner does the same, but I would steer well clear of using anything with WD40 on it for your trains...

 

Andy G

[stewartingram]

3 hours ago, uax6 said:

 

 

WD40 should not be used 

Andy G

There, I've corrected it for ypu! Horrible stuff, the tool of bodgers in my opinion.

 

Stewart

[uax6]

Thanks there Stewart, I agree wholeheartedly with you.

 

Andy g