Triang class 31/37 power bogies

[47164]

I have picked up a kit with 2 triang power bogies, both of which run well now after a good clean, the only problem is that the run in opposite directions when put on the track, and I can't recall how they can be set-up to run in cinque, as in my youth I didn't have this type of issue when running double headed.

Any suggestions appreciated!

[Fat Controller]

I have picked up a kit with 2 triang power bogies, both of which run well now after a good clean, the only problem is that the run in opposite directions when put on the track, and I can't recall how they can be set-up to run in cinque, as in my youth I didn't have this type of issue when running double headed.

Any suggestions appreciated!

Are they the bogies with a worm gear at either end of the motor? If so, look at the spring which keeps the brushes in. On one side, there should be a bit of plastic sleeving which insulates the brush from the spring. Swap this to the other side, along with the wire from the pick-up and both bogies should move in the same direction.

[Titan]

I am not sure that will work for the 31/37 bogie (Think it works for the DMU/Blue pullman/Dock shunter type) 

 

 

Best bet is to dismantle the motor and together turn the poles and magnet around without separating them, and reassemble.

[Nimbus]

Best bet is to dismantle the motor and together turn the poles and magnet around without separating them, and reassemble.

As you'll have to take the armature out of the magnetic circuit, you should put a magnet keeper across the poles before you do. This will reduce magnet weakening.

In the EM2 CKD kit, Tri-ang used to supply the magnet assembly stuck to the steel ballast weight which was destined to be installed over the trailing bogie.

 

The Nim.

[47164]

Many thanks, I will follow your suggestions.

[thaddeus]

just turn the magnet around. remove the black top cap - brush/wiper pickup holder by undoing the longitudinal brass bolt, remove the magnet from the two pole pieces. turn magnet through 180 degrees. rebuild is a reversal of the removal procedure - job done.

[Titan]

just turn the magnet around. remove the black top cap - brush/wiper pickup holder by undoing the longitudinal brass bolt, remove the magnet from the two pole pieces. turn magnet through 180 degrees. rebuild is a reversal of the removal procedure - job done.

 

Except that may demagnetise the magnet somewhat. I would be tempted to replace with neodymium magnets, which may be beneficial as it would reduce current consumption and improve slow speed performance.

[stewartingram]

If you need a remag contact me, I have the tool.

 

Sounds to me that one of the bogies has had the magnet replaced the wrong way round at some point. Think about it - if you had the bogies actually fitted in locos (say a 31 & a 37), it wouldn't matter which way round you put them on the track, they would both go in the same direction if assembled correctly, you could in fact double head them **.

Yours head off in opposite directions, so something is wrong. On these, you cannot change the "wiring", as it is part of the structure, so the magnet needs reversing. But NEVER remove the magnet from its pole pieces/keeper plate, as a loss of magnetism results. As a former service engineer for a number of Hornby dealers, I have the remagnetiser, and can sort this for the cost of postage if required.

 

** Double heading with Hornby motor bogies like these can lead to short circuits, as the chassis of the bogie is live, and if 2 are coupled together in opposite polarities you are coupling +ve to -ve, unless you have insulated couplings.

 

Stewart

[Titan]

** Double heading with Hornby motor bogies like these can lead to short circuits, as the chassis of the bogie is live, and if 2 are coupled together in opposite polarities you are coupling +ve to -ve, unless you have insulated couplings.

 

Stewart

 

I don't think the chassis is intended to be live, as all wheels are insulated and all the copper strip is mounted on plastic insulating it from the chassis.

 

However there are so many ways in which the chassis can become unintentionally live, then it would not surprise me if a large proportion of them were!

 

I recently resuscitated one bought from a car boot sale for a fiver. It was intermittently shorting out. The reason was that a combination of play in the axle bearings plus a narrow back to back was allowing the wheels to rub on the magnadheshon magnets. When the wheels rubbed on opposite corners it short circuited via the chassis. Adjusting the back to backs cured it, as the wheels no longer rubbed making the chassis live.

 

Other ways the chassis can become live is badly adjusted pick up strips, and possibly via the pivot bolt at the top if there is no insulation between that and the magnet below. Also the magnahdesion is good at picking up stray track pins and other pieces of metal which can bridge the insulation to the chassis.

[thaddeus]

Except that may demagnetise the magnet somewhat. I would be tempted to replace with neodymium magnets, which may be beneficial as it would reduce current consumption and improve slow speed performance.

Sorry, but the three seconds it takes to turn a magnet around will not demagnetise it, even slightly. Although I do agree with your neodymium suggestion for the reasons you state

[stewartingram]

Sorry, but the three seconds it takes to turn a magnet around will not demagnetise it, even slightly. Although I do agree with your neodymium suggestion for the reasons you state

 

Rest assured that 3 seconds WILL demagnetise it - during my time servicing them I saw (indeed witnessed) this many times. Lucky is the word if not. Or maybe a partial loss that is not noticeable to the uninitiated.

Edit my earlier post - there were bogie frames that were metal on early examples. From memory, I think the plastic ones came in with the introduction of the pancake ringfields?

 

Stewart

[Nimbus]

Sorry, but the three seconds it takes to turn a magnet around will not demagnetise it, even slightly. Although I do agree with your neodymium suggestion for the reasons you state

The magnetism doesn't just leak away over time. 

 

From http://e-magnetsuk.com/alnico_magnets/characteristics.aspx:

"Alnico does however have a low coercive force, Hc. This means that it is easily demagnetized by external demagnetising fields but it is also very easy to magnetise to saturation. It is therefore possible to magnetise the magnet when part of an assembly (providing the means to magnetise is possible). But, it also means that Alnico may also self demagnetize if the design is poor (it depends on the total magnetic circuit). An example may be removing an Alnico magnet from a motor assembly for inspection and then placing it back and discovering the magnetic output has fallen – putting the magnet in open circuit may be enough to cause self demagnetisation (the working point is taken beyond the ‘knee’ of the Intrinsic curve, causing demagnetisation).; the working point changes if the magnetic circuit changes. "

 

The Nim.

[kevinlms]

I don't think the chassis is intended to be live, as all wheels are insulated and all the copper strip is mounted on plastic insulating it from the chassis.

 

However there are so many ways in which the chassis can become unintentionally live, then it would not surprise me if a large proportion of them were!

 

Early cast bogie chassis were live & if you did as I did & tried double heading with a Jinty, you got a short if the Jinty was coupled to the power bogie. in one direction. If you turned it around it was fine. It's a long time ago & I can't recall which way around worked. The biggest problem was the mismatch of speed, so not recommended, anyway.

[34theletterbetweenB&D]

Sorry, but the three seconds it takes to turn a magnet around will not demagnetise it, even slightly...

 I feel you ought to bear in mind that the materials process control when these were manufactured was not so good. I put a selection of 'good' and 'bad' 1950/60's magnets from open frame motors through the (couple of tons of!) XRD with which the lab group in which I was then employed had been newly equipped in the late seventies. There were significant differences in the crystallography between the 'high field strength, no tendency to lose field when out of magnetic circuit' and the 'flabby, which lost field very readily even when in circuit' groups. (I had to take the expert's word for it, since this is not my field at all. But armed with this XRD kit he was extremely effective in sorting out subtle materials problems that previously caused real difficulties in product engineering; moving us forward in a single leap from 'black art' to quantifiable knowledge, so I am inclined to trust his opinion.)

 

As an FYI: Other analytical work related to model railway, all my own work so I know it is correct...

 

What is the dirt on the rails when there are polymer formulation wheelsets on the layout? Polymer components mostly, some metal oxides.

 

What is the dirt on the rails when there are solely metal wheelsets on the layout? Metal oxides, mainly copper oxide, also nickel, iron, lead, tin oxides,a small organic component, mainly fractions from lubes.

 

So what is happening to the running surfaces of the nickel silver rails and wheels? They become detectably selectively depleted of Copper.

[47164]

Thank you all for a lively and informative debate.... the prize goes to Thaddeus with the 3 second rule in turning around the magnet in the top of the tower!! ...

[thaddeus]

..look at the spring which keeps the brushes in. On one side, there should be a bit of plastic sleeving which insulates the brush from the spring. Swap this to the other side, along with the wire from the pick-up and both bogies should move in the same direction.

you cant do that with the class 31/37 or Hymek unit. The insulated brush spring pushes the brush directly onto the copper pick-up bus which extends into the brush holder. doing that will just cause a short.

 

Best bet is to dismantle the motor and together turn the poles and magnet around without separating them, and reassemble.

you cant do that without removing the magnet from the pole pieces, the armature is also in the way. the pole pieces are keyed into the side frames at the base and are held apart and in position by using the magnet as a sort of "keystone".

 

so, in short this motor cant be serviced or dismantled because the magnet will de-magnetise, even though its obviously been apart before because some "lucky" expert put the magnet back in the wrong way round and probably took longer than 3 seconds doing it.

 

Rest assured that 3 seconds WILL demagnetise it - during my time servicing them I saw (indeed witnessed) this many times. Lucky is the word if not

When servicing these you either didnt dismantle the motor properly or if you did you re-magnetised the magnet every-time?

 

did you bother to test before dismantling? maybe they were already de-magnetised? is that possible? isnt that more likely?

 

how do you witness a magnet de-magnetising on a bench? on a non-working motor how do you measure a motors field magnet while its still in the motor? how do you then measure it against the field after you remove it from the motor?

 

I feel I'm wasting my time here.

[Nimbus]

you cant do that without removing the magnet from the pole pieces, the armature is also in the way. the pole pieces are keyed into the side frames at the base and are held apart and in position by using the magnet as a sort of "keystone".

 

so, in short this motor cant be serviced or dismantled because the magnet will de-magnetise, even though its obviously been apart before because some "lucky" expert put the magnet back in the wrong way round and probably took longer than 3 seconds doing it.

 

Of course it can. Remove brushes. Remove brass retaining/clamping screw though magnet assembly. Remove plastic cap/pickup assembly. Remove base plate. Drop wheelsets and magnadhesion magnets. Push complete magnet assembly, with armature, downwards through bogie frame. Apply keeper to base of magnet poles. Remove armature if required. At this point, the entire magnet assembly could be rotated 180 degrees to reverse direction of travel of the assembled loco relative to applied current polarity. Reassembly is the reverse of dismantling.

 

The Nim.

[stewartingram]

you cant do that with the class 31/37 or Hymek unit. The insulated brush spring pushes the brush directly onto the copper pick-up bus which extends into the brush holder. doing that will just cause a short.

 

 

you cant do that without removing the magnet from the pole pieces, the armature is also in the way. the pole pieces are keyed into the side frames at the base and are held apart and in position by using the magnet as a sort of "keystone".

 

so, in short this motor cant be serviced or dismantled because the magnet will de-magnetise, even though its obviously been apart before because some "lucky" expert put the magnet back in the wrong way round and probably took longer than 3 seconds doing it.

 

 

When servicing these you either didnt dismantle the motor properly or if you did you re-magnetised the magnet every-time?

 

did you bother to test before dismantling? maybe they were already de-magnetised? is that possible? isnt that more likely?

 

how do you witness a magnet de-magnetising on a bench? on a non-working motor how do you measure a motors field magnet while its still in the motor? how do you then measure it against the field after you remove it from the motor?

 

I feel I'm wasting my time here.

 

As a professional engineer in my day job, I ALWAYS test before dismantling, part of normal fault finding.When re-assembled, I always test against known benchmarks. Also if the magnet has been disturbed, I remagnetise anyway. I probably would do intermediate tests before that, and have noticed a fall off in performance if the magnet has been removed (the inexperienced amateur might not though). If dead on receipt, part of the rebuild would include a remag.

As for wasting your time...?

[Clive Mortimore]

I must have been doing things wrong for many years. I cannot recall the number of Tri-ang bogies I have taken apart and rebuilt, never once put the magnet in the wrong way and never noticed a drop in performance. In fact most Tri-ang power bogies I have rebuilt work, when they were non runners before. I must be either lucky or not read the manual properly.

 

Thanks for the advice about the magnets, I will be more careful from now on.

 

Clive

Dog walker, not an engineer so don't understand the fuss.

[New Haven Neil]

I ruined my EM2 as a kid by dismantling it - to see how it worked of course - as it lost magnetism and then overheated and fried the armature.  I later trained in engineering and realised what had happened, a girlfriend's father re-magnetised it years later, as he worked in EM research in Sheffield.  The girl was fun too.....

[john new]

Sorry for reactivating an old thread, the only one even close that search found!

 

I have a replacement keeper plate to replace a broken one. The four tiny cross-head screws are stuck fast, don't want to wreck their heads so I can't refit them.

 

Any tips for freeing them up? All the tips I know of for freeing bolts and stuck screws are for big items not models. Would a drop of WD40 work? (Spray into something then drip on not a total spray over the bogie)

 

I know I could possibly cut through the plastic then use small long nose pliers to unscrew them by gripping the heads but it seems a little over kill.

[andyman7]

15 minutes ago, john new said:

Sorry for reactivating an old thread, the only one even close that search found!

 

I have a replacement keeper plate to replace a broken one. The four tiny cross-head screws are stuck fast, don't want to wreck their heads so I can't refit them.

 

Any tips for freeing them up? All the tips I know of for freeing bolts and stuck screws are for big items not models. Would a drop of WD40 work? (Spray into something then drip on not a total spray over the bogie)

 

I know I could possibly cut through the plastic then use small long nose pliers to unscrew them by gripping the heads but it seems a little over kill.

There are two designs of Keeper. On the earlier ones the screw heads are recessed and flush with the baseplate; later on the moulding was strengthened with the screwheads sitting proud - these later ones left the factory with crosshead screws whilst the flush ones normally had flat bladed screwheads. Which version do you have?

[john new]

Loco is out of reach at the moment.  Memory of the one that needs removing from trying earlier today during  WMRA exhibition is that it has crosshead type screws lying flush at the head.

[33C]

Try tapping them with a hammer, tightening a little bit and then unscrewing. WD40 can't hurt in moderation.

[kevinlms]

11 hours ago, 33C said:

Try tapping them with a hammer, tightening a little bit and then unscrewing. WD40 can't hurt in moderation.

WD40 does affect some plastics, but not immediately. 

The general problem is that the plastic goes brittle and disintegrates.

So you can service all your fleet of models and all is well for a year or more, then...