Hornby dublo

[GoingUnderground]

4 hours ago, Il Grifone said:

 

I realise that Trix is not a true 3 rail system as all the rails are insulated. However the shoe system does make it's pickup reliable. The wheels are coarse enough to enable the point blades to be use as the centre rail. My test track uses an oval of Trix fibre track, which enables me to run 2 or 3 rail (or Trix) locomotives as desired.

The main differences between Trix and Dublo are the ability of the former to run on AC supplies* and the wheel standards.

* It saves a rectifier at the cost of complex, unreliable and expensive sequence reversers.

I think you oversimplifying the Trix story, and could be confusing folsk wh oare not familiar with tRix models.

 

Trix started life in 1935, 3 years before Dublo, as an AC system with coarse scale wheels. In the mid 1950s they finally realised that they had to change and  moved from AC to 12 volts DC, and introduced fine scale wheels.

 

Saying that Trix will run on AC applies to their AC models only. Trix models, such as the AL1, EM1, Warship, Western, and Transpennine DMU only ever had DC motors which used permanent magnets just like Dublo and Triang locos and a permanent magnet DC motor will not run on AC.

 

When Trix introduced fine scale wheels many models were sold as universal, meaning you could run them on Trix's own track or on finer scale track. The universal wheels had a plastic flange moulded to the back of the fine scale wheels to make the flange as deep as the coarse scale wheels. To run the loco on finer scale track you had to remove the flange. This was a one way trip from coarse to fine as the flange had to be cut off and could not be readily reattached.

 

Also Trix DC locos' internal wiring was fundamentally different from Dublo locos, and for that matter from Triang ones. The wheels were completely insulated from the chassis, and the chassis didn't form part of the circuit between track and motor brushes and wasn't live. All pickup was via pickup shoes, not via the wheels, and there were wires to make the circuits between the pickup shoes and the motor brushes. Depending on the orientation of the pickup shoes, you could run a Trix loco on 2 rail, or 3 rail, or in Twin mode picking up from either the left hand or right hand running rail with the centre rail being the common return. Dublo 3 rail locos could only be run on Dublo 3 rail track or on Trix track if it was being used for 3 rail running only.

[Il Grifone]

Perhaps I was over-simplifying. I was relating the coarse wheels to the AC system overlooking their later 'universal' (with the plastic ring) and scale (i.e. Dublo standard) wheels associated with their conversion to DC. Obviously uninsulated wheels are incompatible either with 2 rail  or the Trix Twin system.

 

The only Trix DC locos I have are a pair of 56xx 0-6-2Ts*, so I can't speak for the others, but these are wired the other way round to Dublo 3 rail with the chassis live to the centre rail (like the AC locomotives). This causes shorting problems with Dublo 3 rail stock which is live to the running rails (as I found out when I bought the first one (1959 IIRC). Fitting the later plastic couplings solves this, but something needs to be done about the uncoupling trip pins which are set for the old coarse wheels.

 

*A minor (but painful) point here is that the coupling rods have a sharp point at the top. Catching my finger between rod and running plate a few (too many)  times persuaded me to take a file to them!

[GoingUnderground]

Unlike you, I have a clutch of EM1s, including one that I acquired around 1970 which already had a motor bogie gearbox suffering from Zinc pest, as well as an AL1, some Warships that are intended as donors for restoration of some EM1s, a Western, and a Transpennine EMU, all DC. It is those locos that give me my experience of Trix.

 

And I was also a bit economical with the truth. The EM1 could also be run to pick up from the Trix catenary system, in which case It only needed pickup shoes for the centre rail common return. Thus only Trix could say that they had a system that offered the possibility of 3 trains under independent control.

[Il Grifone]

Yes, you can have 3 EM1s and have them all under independent control. I always intended to have an overhead electrified system, but it's one of those (many) things I never got around to.

 

I've converted all my Trix AC locos to DC with bridge rectifiers, with the exception of the 'Scotsman'. The sequence reverser works properly on this one though the automatic uncoupler is hit and miss. It's rather a useless feature anyway, so I decided to leave well alone.

 

I have a Lima 'Western' so I don't need a Trix one....

 

Trix really went for the common return system in a big way. All the accessories returned via the centre rail. Dublo tried, but weren't 100% successful (pushbutton for the TPO in the return path for example!).

Edited May 19, 2021 by Il Grifone

[sagaguy]

Still playing with Hornby Dublo,A modern Hornby spamcan on a vintage layout.One of the easier conversions,a Marklin skate and one wire cut and rerouted to the motor.Very impressive models,21C 7 to do next.

                    Ray.

[GoingUnderground]

You know, I admire your dedication to HD 3 rail in converting 2 rail locos to 3 rail. I'm afraid that HD never impressed me, and the only HD models that I have are the 2 rail versions of the EMU, the Co-Bo, and the AL1 which I had specific reasons for buying.

 

Clearly you love HD as much as I love Triang, and I take my hat off to you.

[sagaguy]

On 30/05/2021 at 10:28, GoingUnderground said:

You know, I admire your dedication to HD 3 rail in converting 2 rail locos to 3 rail. I'm afraid that HD never impressed me, and the only HD models that I have are the 2 rail versions of the EMU, the Co-Bo, and the AL1 which I had specific reasons for buying.

 

Clearly you love HD as much as I love Triang, and I take my hat off to you.

Call it nostalgia, this is a photo of my Hornby Dublo layout in the 1950s when i was a child.Having gone through a long life of model railways,i have used most gauges,N to 00 to 5" gauge live steam but it seems to come back to my original interest.

 

                                    Ray.

[Downbytheriver]

Good day to you gentlemen. When I was a lad I was given a lovely 3 Rail set with a 2-6-4T tank and a few extra wagons, points and other track. I loved it but was never able to set up a baseboard and eventually it went into storage, perhaps never to be seen again... 

 

However I am now in possession of a LOT of track (obviously not enough, but that might change soon, and I have loads to move on!) a N2 and a Sir Nigel Greeley A4, wagons and carriages. And a baseboard. And the bible. And 3 books of layouts! So I have started setting up. The N2 runs wonderfully round the track as it stands but the A4 is not interested! 
 

so I come to my question... 

 

Where do I start? I am very keen to get the A4 running. Is there any basic guidance anywhere? 

many thanks, Stan

[sagaguy]

If you are a facebook member,you could do worse than have a look here.  Hornby Dublo Enthusiasts page.Plenty of advice on there almost solely Hornby Dublo but i do sneak in modern and not so modern conversions to operate on 3 rail.

 

                            Ray.

[Hroth]

1 hour ago, Downbytheriver said:

so I come to my question... 

 

Where do I start? I am very keen to get the A4 running. Is there any basic guidance anywhere? 

many thanks, Stan

Some things to try

 

1. If you have a multimeter, check that the path from the third rail pickup to the brushholder is conductive, the wire at the pickup end might be disconnected.
2. Check that the gearing isn't gummed up with old oil. Try cleaning around with a cottonwool bud moistened with isopropyl alcohol.  If you don't have any a small quantity of plain vodka will do!  Then apply a drop or two of light oil. A drop on the top and bottom armature bearings will help too.
3. Clean the commutator with a cottonwool bud moistened with isopropyl alcohol as mentioned above.  Then scrape out the slots with a cocktail stick.
4. I can't see what the armature windings are like. If they look rather blackened they might have burned out and you'll have to look for a replacement...
5. That interference supressor condenser (or capacitor) looks rather worrisome, waxed paper is something that I would expect to see in pre-war wireless sets.  It may well be that the internal insulation has broken down and its shorting to earth.  First test would be to disconnect it and see if there's any improvement.  If that works, then you'll have to replace it with a more modern 0.1uF capacitor. They're considerably smaller, so don't worry!
6. The magnet may have lost a lot of its power.  It might be a good idea to try a temporary fix with a neodynum* magnet to give it a boost.

 

Hornby Dublo motors are fairly robust so those are the most common points to examine.

Hope that helps!

 

* However you spell it!

 

 

Edited July 18, 2021 by Hroth
Just a bit of post-posting proofreading...

[Downbytheriver]

Many thanks - I shall get stuck in! 
 

stan 

[Il Grifone]

The capacitor is unlikely to be faulty, despite its grotty appearance (This one is actually quite good!). Simple to check just undo the front bogie, though if faulty (short circuit) it will trip the overload cut-out. Open circuit it will of course have no effect. In later models this component was reduced in value to 470pf to improve suppression at VHF TV frequencies with the addition of an inductor. I'd leave it alone for originality.

It looks a nice clean chassis*, so well worth repairing. I find Humbrol 85 coal black is a good match.

 

Zooming in on the picture I noticed the armature top bearing is screwed right down and its locknut is loose. I'd check this first. It should have just perceptible movement up and down. The connection to the brush cap looks dry jointed, though this is unlikely to prevent it working.

 

*The zoom also revealed the gouge in the casting. Check this is not the dreaded pest. If so a new block (from eBay) is required. Take care to preserve the magnet with a keeper if dismantling. It should be able to support a small pair of pliers.

 

Dublo track is quite cheap (once the fairs get going again). Avoid any with bent base plates (trodden on!) and the Korean war stuff -steel rail and/or cardboard centre rail isolating plates.

 

Neodymium - It's a rare earth element.

https://en.wikipedia.org/wiki/Neodymium

Edited July 18, 2021 by Il Grifone

[Hroth]

15 hours ago, Il Grifone said:

Zooming in on the picture I noticed the armature top bearing is screwed right down and its locknut is loose. I'd check this first. It should have just perceptible movement up and down. The connection to the brush cap looks dry jointed, though this is unlikely to prevent it working.

 

A good point.  I've not had my Silver King opened for a long time so I didn't notice that. If the rear driver is gently rocked to and fro, there should be a slight click as the armature moves against its bearings.  Zooming in also seems to reveal that the worm on the armature isn't well defined, it looks as if its gummed up with old oil and dirt.  Freeing that up may do the motor a power of good!

[Il Grifone]

Crud is unlikely to stop the locomotive working at all, but will ensure she can't give of her best.

All my 'new' stock gets a service in the first days in its new home.

[Lacathedrale]

I've a few questions re: a potential 3-rail layout build, if that's OK?

 

What kind of gradient can 3-rail dublo deal with? Let's say for the sake of argument with three tinplate coaches behind the 'average' locomotive?

 

Is there a track planning set of stencils I can use?

Edited July 20, 2021 by Lacathedrale

[Downbytheriver]

On 20/07/2021 at 10:32, Lacathedrale said:

Is there a track planning set of stencils I can use?

I’ve used the free version of SCARM software on a PC - it has Dublo 3 rail track in it - very helpful for planning! 

Edited July 21, 2021 by Downbytheriver

[Il Grifone]

IIRC tests in the model press back in the day showed a tractive effort of a Dublo locomotive at around 50g. My own test (for what it's worth) showed a Stanier coach to require 8g to move it. This fits with my experience of Dublo Pacifics being able to haul five coaches. (The tank engines would handle a couple more (counting the tender as one coach) and the diesels with traction tyres and the heavy West Country are more powerful (very much so in the case of the Co-Co and Co-Bo). I find nickel plated drivers to have less grip than the plain alloy.

The Dublo specification was for rolling stock to start from rest on a 1 in 30 gradient (which shows a rather high bearing friction. (Pin-point bearings will reduce the gradient to 1 in 100.)

Hence the coach will require about twice the pull up a 1 in 30 gradient. It follows that two coaches are all that can be managed on 1 in 30 and three will probably need the gradient to be around 1 in 40.

Some more accurate tests are really needed, but I haven't any Dublo locomotives to hand at the moment. 

 

Edited July 21, 2021 by Il Grifone

[Downbytheriver]

Well, I’ve had a fun Saturday cleaning, oiling and adjusting locos and everything is running better and smoother which is gratifying! 
 

However, the one exception is Sir Nigel Greeley who is determinedly unresponsive in every way. Everything is clean and turns easily. I’ve changed both the armature and the magnet. I’ve checked continuities from middle rail to brush holder and from outer rails to body etc. I’ve established (I think) that brush is in contact. I can’t find any shorts. I’m approaching my wits end. How stupid am I being? 

 

[sagaguy]

First thing is to check continuity across the commutator through the brushes, I personally don't use rewound armatures,too many are faulty before you buy them.I always send my chassis to Scalespeed, for what he charges for a full service,it's not worth buying armatures. 

 

      Ray. 

[Downbytheriver]

Thanks Ray - you’re right, there isn’t continuity across the brush holders. You are also right - Scalespeed looks like a good option! 
 

Stan

[cypherman]

7 hours ago, Downbytheriver said:

Well, I’ve had a fun Saturday cleaning, oiling and adjusting locos and everything is running better and smoother which is gratifying! 
 

However, the one exception is Sir Nigel Greeley who is determinedly unresponsive in every way. Everything is clean and turns easily. I’ve changed both the armature and the magnet. I’ve checked continuities from middle rail to brush holder and from outer rails to body etc. I’ve established (I think) that brush is in contact. I can’t find any shorts. I’m approaching my wits end. How stupid am I being? 

 

Hi Stan,

Have you seen Ronald Dodds videos on maintaining and servicing Hornby Dublo engines. They are on You Tube. Here is the link to the servicing of motors. I hope you find this some help.

 

[sagaguy]

The thing is that most of the armatures on offer are second hand recovered from broken down models for spares,probably faulty before you start.On the subject of magnets,i personally will not use neo magnets,they are too powerful,if you mess about packing them with card or whatever,you`ve missed the point.I bought one of Rons remaggers,whipped any neo magnets out and replaced them with original Alnico magnets and remagnetised them in the correct manner.I would never take a magnet out of a dublo loco(except ringfield magnets which don`t lose their magnetism)unless you have the equipment to remagnetise the whole motor as the armature is part of the magnetic field.

 

                                Ray.

Edited July 25, 2021 by sagaguy

[Il Grifone]

The brushes are not above sticking in the tubes. Crud collects here too, especially if a previous owner was overgenerous will the oil. Check the springs too as these are prone to damage.  continuity through the windings should also be checked. Unlike Tri-ang motors which are delta wound*, Dublo are star wound and between adjacent segments there will be the resistance of two windings (about forty ohms or so  IIRC). Obviously you should get the same reading between any two segments.  I find the soldered joint between the winding and the commutator is often dry or broken and can be resoldered. If necessary a turn can be removed without noticeable effect.

 

* In the case of Tri-ang, you will be measuring one winding in parallel with the other two in series around 10 ohms (IIRC each winding measures 22 ohms).

[locomad2]

On 21/07/2021 at 22:46, Il Grifone said:

IIRC tests in the model press back in the day showed a tractive effort of a Dublo locomotive at around 50g. My own test (for what it's worth) showed a Stanier coach to require 8g to move it. This fits with my experience of Dublo Pacifics being able to haul five coaches. (The tank engines would handle a couple more (counting the tender as one coach) and the diesels with traction tyres and the heavy West Country are more powerful (very much so in the case of the Co-Co and Co-Bo). I find nickel plated drivers to have less grip than the plain alloy.

The Dublo specification was for rolling stock to start from rest on a 1 in 30 gradient (which shows a rather high bearing friction. (Pin-point bearings will reduce the gradient to 1 in 100.)

Hence the coach will require about twice the pull up a 1 in 30 gradient. It follows that two coaches are all that can be managed on 1 in 30 and three will probably need the gradient to be around 1 in 40.

Some more accurate tests are really needed, but I haven't any Dublo locomotives to hand at the moment. 

 

Generally agree with above, having a test rig modelled on  "Model railway Constructor " mid 70's which published traction fiqures for locomotives available at the time, most Hornby dublo locos I've got roughly follow what was obtained then.

 

However some locomotives are real pigs and others run beautifully, I've quite a few 2 rail 2-6-4 MT's some have  excellent haulage capacity others just don't run right dispite trying to get them to all work the same. Experience has taught us over 50 years that constant use on several past layouts obtain the best results, those locomotives left for long periods in boxes tend not to run or haul as well.

 

As my layouts have got generally larger its possible to run larger trains, 12 coaches the norm and 40 wagons for freight, as expected only Hornby Dublo, Wrenn and Triang Hornby X04 motor types are almost the only motive power left, only the early T/H 9F, now almost 50 years old, out performs the others in haulage capacity. 

 

One day I might just publish the actual haulage capacity of current stock prehaps a retirement project 

[Il Grifone]

My collection of Dublo N2s (Not saying how many - despite being British, I plead the Fifth Amendment) are rather variable in performance. The best is my Southern Railway version. It doesn't seem to be a question of armature or magnet. It's probably a sum of all the various tolerances....

 

Dublo rolling stock is not particularly free running* and rather heavy. Pin-point bearings would help at the cost of originality.

 

* The 1950s sintered iron wheel is particularly bad - all square - mitigated in part by the round headed Dublo rail. The original alloy and later plastic wheels are much better. Even 1920s Hornby 0 gauge has tapered tyres and flanges so really there is no excuse for this aberration.

The Dublo specification of starting on 1 in 30 is not very impressive though some of my American stock isn't much better despite pin-point bearings (Get rid of those plastic wheelsets David!).