Trix Twin Railway, How do I convert one from 3 Rail to 2 rail DC? (asking on behalf of a Friend)

[Max's Model Railway]

Hello, I'm Asking on behalf of a Friend, who's got a Twin Trix Railway 3 Rail British Railways Blue Flying Scotsman and I want to know how easy it would be to convert the model over to 2 rail DC,  If it would be a simple matter of replacing the magnets and Amateur on the Locomotive or if it would need further modification such as a wheel replacement Can anyone offer any advice? He doesn't run 3 rail... 99% of his models are 2 rail. Thanks for the Help! he's in Canada so models from the UK won't be Available to an extent, So American models will have to be used

Edited June 20, 2020 by Max's Model Railway
Mistake in the final product

[PatB]

I expect someone with proper experience of TTR will chime in shortly but, for the time being, here's the perspective of someone with a little electrical knowledge and an interest in converting AC locos from other manufacturers to DC operation.

 

Firstly, as TTR depended on the use of isolation between the running rails to work as advertised, lfe should be a little easier than it might be otherwise, as the loco will already have insulated wheels on one or both sides. How pickups would need to be arranged will depend on how this insulation is done and how Trix intended the existing pickup from the running rails to work.

 

Secondly, obviously the centre rail pickups will need to come off. The wire from it will need to be connected to whatever pickups you fit to the side of the loco that doesn't pick up from the running rail as standard.

 

Finally, there's the matter of the motor. I understand that Trix  used a wound field motor for running on AC. Such motors are also known as universal motors, because they will also run very happily on DC. In fact, they are often rather smoother and more controllable on DC. However, they will not self-reverse on either AC or DC. On their own, they will run in one direction only, determined by the motor's internal wiring arrangement. Reversing is achieved with a mechanical switch, either manual or an electromechanical arrangement of some sort. My own interest is in US made Marx and Lionel equipment, which are AC powered and both utilise electromechanical reversers, which operate automatically each time the traction current is interrupted. These units operate perfectly happily on DC too. I would assume that Trix used something similar but, obviously, smaller, which might also operate quite well on DC.

 

However, electromechanical reversing is, TBH, a bit of a pain. Dirty track can lead to unscheduled reversals, stopping and starting can require a few undignified shuffles to get the reverser sorted out, and the reverser unit, generally being a permanently actuated electromagnet, tends to get a bit hot. If you're running on DC, it makes much more sense to wire the universal motor to reverse by simply reversing the current direction as we do with conventional, permanent magnet motors. This is fairly straightforward, but requires a little soldering and some rudimentary electrical knowledge. On something as small as 00 it might be a little bit fiddly as well. I'm used to working in the roomy interiors of US 0 gauge equipment.

 

In principle, what is required is to ensure that the current in either the armature or the field coil (but not both) will always flow in the same direction, regardless of the polarity of the running rails. On the Marx locos I've been converting, the field coil is easier, but either will work.

 

The only additional component you need is a small bridge rectifier. For a 00 loco something with a 1A currrent capacity should be ample, and will be pennies from your friendly electronics shop (if you have one). This is a suitable one from mine. If you're not familiar with what a bridge rectifier is, or does, it's a rather clever component with two input terminals and two output terminals and is arranged such that, regardless of the electrical polarity of the input terminals, the +ve output will always be +ve, and the -ve will be -ve. The input terminals will be marked with ~, and the outputs + and -.

 

Assuming that a Trix motor is arranged similarly to the Marx ones I'm used to, you need to identify the wires leading to each end of the field coil, and disconnect or cut them, leaving sufficient "tail" on all the cut ends to connect to the terminals of the bridge rectifier. Now the + and - terminals of the rectifier need to be connected to each end of the field coil. Which way round doesn't matter from a functional point of view, but will dictate which way the loco will go with your controller set to "forward", so you might want to test that before buttoning everything up permanently. The ~ legs of the rectifier now need to be connected to the remaining loose tails left after you cut the wires. It's a good idea to insulate everything with heat-shrink tubing so nothing shorts in use. You might have to add some thin leads to extend things so that the rectifier can be sited where there's some convenient space in the smokebox or cab. You will also need to trace the wiring that operates the old reverser unit and disconnect it, or it will still attempt to operate when the traction current is shut off. Or you could remove the reverser entirely. Marx and Lionel unites have significant monetary value on Ebay, so there might be some benefit to selling it, if there is no likelihood of the loco needing to be returned to standard.

 

And that's it. All being well, your electromechanically reversing AC motor is now an automatically reversing DC motor. Be warned, attempting to operate the converted loco on AC will have a similarly detrimental effect as doing so with a conventional permanent magnet motor (buzzing and escape of the magic smoke).

[Il Grifone]

First of all, a TTR blue Scotsman is an extremely rare collectable, so any modifications should be reversible and exercised with extreme care.

 

Secondly Trix wheels are extremely coarse and will only run through Trix or 'universal' pointwork, so the viability of the conversion has to take this into consideration. Replacement of the wheels is not an option as the drive is through teeth cast into the back of the driving wheel flanges.

 

The sequence reverser will operate on DC as it functions whenever the supply voltage drops below 4 volts (Trix brush tension (adjusted with the two screwed brush caps on the side of the locomotive) should be set so that the locomotives stops with a supply less than six volts - the system relies on continuous voltage on the rails - a bit dodgy as leaving locomotives stopped under tension can cause them to overheat. I have converted all my Trix locomotives except my Scotsman, which runs well and being an express locomotive does not really need to reverse much. Her reverser (unusually) works properly (it is a very temperamental device!). Though a BR green example she is still quite valuable so I prefer to leave her alone!

 

Conversion to DC is fairly easy using a bridge rectifier as in the previous post, but disables the remote uncoupling feature which operates through the sequence reverser. It's pretty useless IMHO so not a great loss.

Trix locomotives pick up from one of the running rails and return via the centre rail which is the common return. This is done with spade connectors and these can be adjusted to pick up from either running rail (the Twin system). Some sort of pickup, possibly to the backs of the non-geared wheels, will have to be devised to replace the centre rail pick up, leaving the original pickups to pick up from the geared side. Tender pickups are also a possibility. There is a convenient plug and socket which feeds the uncoupling device in the tender.

 

It is possible that the chassis of a Tri-ang 'Princess' will fit in the locomotive*. These have the advantage of being quite common and cheap (probably even in Canada?). I was going to do this with my Trix 'Princess', but zinc pest had got there first and distorted the body. (Her original chassis had disappeared before I acquired her. Probably it had disintegrated with the pest.

 

* The Trix Pacific chassis was fitted originally to a German 01 Pacific and then to an Americanised version of this (fooled nobody! - cf the Dublo CPR Duchess). Then there were three British locomotives the LNER 'Scotsman' and two seriously under length LMS locomotives, a 'Princess' and a Streamlined 'Coronation'. My theory is that the Rovex (later Tri-ang) ' Princess' was copied from this Trix model, which would account for the similar length of the models

 

[Il Grifone]

I forgot to mention that the 'Scotsman' was supposed to run a 'scale speed' which translates to about 70 mph, at least for mine). Since the chassis was originally intended for an H0 scale DRG 01 Pacific (which explains the odd wheelbase), this would be perhaps 80/90 so more reasonable. The LNER Pacific (presumably an A1- later A10) is nearer 00, but Trix could never make up their mind as to what scale their British models were (it varies from 1:90 to 1:76 in their literature! A year book (1956 IIRC) I have quotes a mile as 60 foot six inches).

 

The rarity of the Scotsman is accounted for quite easily. Pre-war models were/are seriously affected by zinc pest and post war were limited by material shortages and sales were affected by the generally high price and limited availability of Trix compared to Dublo and later Tri-ang. (A Trix 'Scotsman' cost around £10 when you could obtain a Dublo A4 or Duchess for around £4). Add to this the short existence of the blue livery, zinc pest*, and limited production due to the Korean War and you have a very rare model. Even the relatively common BR green version is quite valuable.

 

*Post war Dublo seems immune, but unhappily Trix is not. The rear pony truck of mine was seriously affected.

 

Sorry for waffling on. My daughter is always saying I should be more concise. I blame writing essays at school. Filling three foolscap (A4 now) pages on subjects I couldn't care less about....

[Max's Model Railway]

10 hours ago, Il Grifone said:

it is possible that the chassis of a Tri-ang 'Princess' will fit in the locomotive*. These have the advantage of being quite common and cheap (probably even in Canada?). I was going to do this with my Trix 'Princess', but zinc pest had got there first and distorted the body. (Her original chassis had disappeared before I acquired her. Probably it had disintegrated with the pest.

Will any princess chassis's work? even the oldest Tri-ang (Non Rovex) Models, how'd I Isolate the body from the chassis, Assuming He'd have the same problem when Awdry Converted his Henry (Graham Farish Black 5) to Use a Tri-ang Chassis, I know Romford wheels are an option, is there a simple way to Convert one? If romford wheels were not an option and they are not for me how would one would?

[sagaguy]

If you are on Facebook,check out the Trix Model trains group,between them & the TTRCA,there is a fount of knowledge.As Griff says,the loco is extremly rare,if he wants a loco to run on modern track,he`d be better buying a modern model.For TTR spares,the only real source is the TTRCA but you have to be a member to buy.

 

                            Ray.

[Il Grifone]

11 hours ago, Max's Model Railway said:

Will any princess chassis's work? even the oldest Tri-ang (Non Rovex) Models, how'd I Isolate the body from the chassis, Assuming He'd have the same problem when Awdry Converted his Henry (Graham Farish Black 5) to Use a Tri-ang Chassis, I know Romford wheels are an option, is there a simple way to Convert one? If romford wheels were not an option and they are not for me how would one would?

 

I doubt that it would be necessary to isolate the body from the chassis. Dublo never found it necessary. In any case all insulated drivers and new pickups ( also insulate both motor brushes) would permit a neutral chassis. Romford wheels would be fine, but need bushing (9/64" to 1/8"). washers will be needed behind the wheels to curb the slop. I believe 9/64" axles are available, but prefer the brass bushes. The Tri-ang chassis has plastic cylinders and motion bracket so insulation is not a problem. The return cranks will have to be soldered to the crank pin or the wheels drilled for the Tri-ang pins (which just push out of the wheels). This enables Tri-ang's error of not having left and right handed cranks to be corrected.

Edited June 21, 2020 by Il Grifone

[Matt C]

Check out the value of it BEFORE you do any conversion. If it IS rare and valuable and he has no interest in it other than wanting something to run, it may well be worth joining the group mentioned above and see about selling it on and using the cash to buy some more suitable OO ?  

[Il Grifone]

It is rare and valuable.

 

Some Philistine has taken one apart here and is selling the bits separately:

 

https://www.ebay.co.uk/b/Flying-Scotsman-Vintage-OO-Gauge-Model-Railway-Locomotives/122604/bn_7025390019

 

The chassis alone has already made 60 quid!

 

Or this repainted one with a fake box (admittedly it has been done well, but a repaint is only worth about a third of a mint original example at best. (A fake reproduction box is a fake box.)

 

https://www.vectis.co.uk/lot/trix-ttr-steam-outline-locomotive-4-6-2-scotsman-no60103-in_530446

 

I don't think I'm giving away trade secrets when I say it made £200 (you only have to open a free (Grifone friendly price!  ) account.)

[Grovenor]

Well £185 all up does not seem all that high! But at least there are good pictures to help the OP. It looks as though all the pickup shoes are on the tender.

IMHO trying to convert it to 2 rail is a waste of time, just buy a recent Scotsman if one is wanted, sell the TRIX or if it has sentimental value showcase it.

[Matt C]

My thoughts were along the lines of, join the trix club, find someone interested who dabbles in both, agree a value, and then set up an exchange 3 rail for 2 rail, each covering the cost of postage to the other. Cuts out any middle man and fees

[Grovenor]

You can try that, Trix did make a much nicer 2-rail Scotsman.

[Il Grifone]

2 hours ago, Grovenor said:

Well £185 all up does not seem all that high! But at least there are good pictures to help the OP. It looks as though all the pickup shoes are on the tender.

IMHO trying to convert it to 2 rail is a waste of time, just buy a recent Scotsman if one is wanted, sell the TRIX or if it has sentimental value showcase it.

 

It is the starting price and might sell for that, but probably will go considerably higher.

 

Other models of a Gresley Pacific are available. Most/all are rather better and cheaper and already 2 rail.

[sagaguy]

Does it have to be an A3,Trix made a very nice A2,A,H,Peppercorn in 2 rail,i converted mine to 3 Rail.A word of warning,buy a loco drive mode,tender drives have a habit of  cracking of the chassis.

 

                         

 

[Philou]

Just on a point raised above regarding H/D and their polarity (I assume we talking 3-rail), it didn't matter with H/D as the outer rails were the same polarity and it made no difference, whereas with Trix, the common rail was the centre one and the outer ones could be wired up separately via two controllers or if you were really clever and you had one of their electric locos, you could have THREE locos running independently using the centre rail as common return. Pah! Who needed DCC all those years ago? Get off my lawn .... mumble mumble.

 

If the loco is indeed valuable, I would leave it alone and NOT convert it. I converted the Trix Britannia and the 73xxx to two rail by using H/D wheels that were insulated with a plastic bush (as per the original 2-rail H/D) on the original Trix axles. I left the centre drivers alone - it looked a little odd given that the Trix wheels were over-wide - we are talking of the late 60s here. It worked but ideally it should have been a complete re-wheel using Romfords (or Markits or other) but the Trix axles are of a smaller diameter so to do it seriously, you need to open out the axles holes in the chassis too!

 

Cheers,

 

Philip

[Il Grifone]

To be pedantic (just for a change  ), the Trix 'Scotsman' dates from the thirties before reboilering and is thus an A1 (later A10). Where this is really relevant considering the approximation to reality represented by the model, I'll leave you to decide for yourself.

[Max's Model Railway]

On 21/06/2020 at 05:17, Il Grifone said:

 

I doubt that it would be necessary to isolate the body from the chassis. Dublo never found it necessary. In any case all insulated drivers and new pickups ( also insulate both motor brushes) would permit a neutral chassis. Romford wheels would be fine, but need bushing (9/64" to 1/8"). washers will be needed behind the wheels to curb the slop. I believe 9/64" axles are available, but prefer the brass bushes. The Tri-ang chassis has plastic cylinders and motion bracket so insulation is not a problem. The return cranks will have to be soldered to the crank pin or the wheels drilled for the Tri-ang pins (which just push out of the wheels). This enables Tri-ang's error of not having left and right handed cranks to be corrected.

Yes I understand however sadly In my Country (the states) its hard to come across a pair of romford Anything, Let alone axles and wheels in the right size, Hence why I was implying it might be difficult to obtian Some,  That and import taxes are pretty expensive now. Hence why I'd like to find something mor available if possible. Thanks for any advice.

Edited August 6, 2020 by Max's Model Railway
Less confusing

[Max's Model Railway]

On 21/06/2020 at 12:23, Philou said:

Just on a point raised above regarding H/D and their polarity (I assume we talking 3-rail), it didn't matter with H/D as the outer rails were the same polarity and it made no difference, whereas with Trix, the common rail was the centre one and the outer ones could be wired up separately via two controllers or if you were really clever and you had one of their electric locos, you could have THREE locos running independently using the centre rail as common return. Pah! Who needed DCC all those years ago? Get off my lawn .... mumble mumble.

 

If the loco is indeed valuable, I would leave it alone and NOT convert it. I converted the Trix Britannia and the 73xxx to two rail by using H/D wheels that were insulated with a plastic bush (as per the original 2-rail H/D) on the original Trix axles. I left the centre drivers alone - it looked a little odd given that the Trix wheels were over-wide - we are talking of the late 60s here. It worked but ideally it should have been a complete re-wheel using Romfords (or Markits or other) but the Trix axles are of a smaller diameter so to do it seriously, you need to open out the axles holes in the chassis too!

 

Cheers,

 

Philip

Thanks for the imput Philip, my Friend has no 3 rail track of any kind, Hence why I was suggesting this as a possibility. He mainly has a bunch of 2 Rail Stuff, 

 

This may find you handy

 

https://youtu.be/i9musWnowmc

[Il Grifone]

Trix Twin/Express wheels, as fitted to the 'Scotsman', are rather coarse and require something on the lines of code 150 rail and 3mm flangeways. 'Universal' track (to accept Trix wheels) required point levers with a 3/16" throw, rather than the 'normal' 1/8".

 

Rivarossi Hiawathas (unlike the Tri-ang CPR one!) are very rare and collectable. Apart from their high first cost (which meant there weren't many to start with!), they are extremely liable to the dreaded zincpest.

 

We are very jealous of your basements on this side of the pond! 

Edited August 7, 2020 by Il Grifone

[Max's Model Railway]

On 07/08/2020 at 04:33, Il Grifone said:

 

We are very jealous of your basements on this side of the pond! 

its not my basement its my Friends, I'm Jelous of it, Here's mine, which is about a 1/4 of it

[Il Grifone]

it's still bigger than mine - zero!  

[GoingUnderground]

On 09/08/2020 at 15:35, Max's Model Railway said:

its not my basement its my Friends, I'm Jelous of it, Here's mine, which is about a 1/4 of it

 

What make of track is that? It doesn't look like British Trix track as their "ballasted" track had a black bakelite base, and I don't think they ever used a metal base as that's what the track in the picture seems to have.

 

A couple of thoughts for you on your friend's blue Scotsman. First, it was only made in 1951 and 1952. Also if the tender is the original one, it should have a solenoid in it which operates the coupler to allow remote uncoupling. I don't know whether that would survive conversion to DC.

 

 

[Silverfox17]

5 hours ago, GoingUnderground said:

 

What make of track is that? It doesn't look like British Trix track as their "ballasted" track had a black bakelite base, and I don't think they ever used a metal base as that's what the track in the picture seems to have.

 

A couple of thoughts for you on your friend's blue Scotsman. First, it was only made in 1951 and 1952. Also if the tender is the original one, it should have a solenoid in it which operates the coupler to allow remote uncoupling. I don't know whether that would survive conversion to DC.

 

 

The track is Marklin and is the older version with a 3rd rail, the later one had a blackened steel stud contact strip. The base is aluminium with the sleepers pressed into it not just printed on like Dublo. It will join directly to Dublo although slightly higher but the points have wider check rails. Dublo locos will run on the stud contact but the shoes click on each stud so I inverted it to be a 3rd rail above and being blackened it was not as noticeable. 

 

Garry 

[Silverfox17]

On 21/06/2020 at 17:22, sagaguy said:

Does it have to be an A3,Trix made a very nice A2,A,H,Peppercorn

Trix also made an A3 as well as the A2 and A4. The Scotsman was available with a second tender as it came out after the real one had received a second tender. It was just a second tender though with a coal load and standard front end. 

 

Garry 

[GoingUnderground]

3 hours ago, Silverfox17 said:

The track is Marklin and is the older version with a 3rd rail, the later one had a blackened steel stud contact strip. The base is aluminium with the sleepers pressed into it not just printed on like Dublo. It will join directly to Dublo although slightly higher but the points have wider check rails. Dublo locos will run on the stud contact but the shoes click on each stud so I inverted it to be a 3rd rail above and being blackened it was not as noticeable. 

 

Garry 

Thank you. That's what I thought. Maerklin "M" track, as it didn't look like Dublo. but I'm not an expert on 3 rail track, and I've been caught out before.