Dublo-Wrenn Comparison

[Nearholmer]

Can I consult the collective wisdom of the collectable/vintage eminences grise?

 

Is there any material/practical difference between 2-rail HD locos and their Wrenn successors? To put it another way did Wrenn improve (or degrade) the function of the products?

 

I ask because there seems to be a noticeable difference in second-hand prices, with Wrenn attracting a premium even for superficially identical items, and I'm trying to understand whether this is simply down to Wrenn being newer, more fashionable, or in shorter supply, or whether there are qualitative differences.

 

Clearly Wrenn (I loose track of all the ownership iterations thereof) understood early the potential of the collector market, by making all sorts of (often eye-poking) livery variants, but that is not at all "my sort of thing", in fact I find it a bit irritating that they put all sorts of weird logos all over perfectly good basic wagons, so my question is confined to "sensible things" produced under both labels.

 

Thanks in advance, Kevin

[andyman7]

There was some reengineering of models - I'm not the expert but for example I understand that the Wrenn era City/Duchess uses the A4 mechanism rather than the one HD used. The least valuable Wrenn items seem to be the ones that are essentially HD reissues but I wouldn't underestimate the usefulness of the Triang couplings - these are crimped in pace on spigots cast into the chassis that are missing on the HD versions.

 

I'm not sure that the collectors market was the sole focus of all the liveries rather than a small company sweating the tools for all they were worth. The documented production figures are quite eye-opening, with production of items in their 000s in the 1970s dwindling to issues in some case of under 100 for mid 80s to end of production in 1992.  

[sagaguy]

There are some differences,there are at least three different chassis blocks for the fixing of the body.The N2? ,0-6-2,uses the R1 chassis with a rear truck tacked on.The rebuilt WCs seem to be popular but a far cry in price from the new Dublo models in the 60s.The names of the city locos seem to cause some excitement price wise.The models that appear to command high prices are the Spamcans,(i`ve got three converted to 3 rail)& the Royal Scots,diecast with parallel boilers.There is something about the weight of these locos that sets them apart from Hornby models.

 

                     Ray

[Wolseley]

The rear fixing of the chassis to the body and the positioning of the bolt at the front are different on the Wrenn Cities/Princess Coronations compared to the Dublo version.  I have no idea why they did this, as the rest of the chassis looks the same.

[sagaguy]

The late City chassis had a different fixing at cab end,this cosisted of a plastic plate which was screwed to the rear of the chassis & engaged in a slot in the body under the cab.This plate is hard to find these days,you can see it in the pic below.The spamcan has its own unique chassis.

 

                                Ray.

[Nearholmer]

EE 350hp, EE 1000hp, R1, 4MT tank? The same under both labels?

[sagaguy]

The Bo Bo was a different design,the R1 was the same as the Dublo version,Shunter ,the same as the Dublo model & as far as i know,the same chassis.The Wrenn Brighton Belle had a chassis that was unique  to that model.

 

                                           Ray.

[Il Grifone]

The DE shunter was retooled by Wrenn as Dublo had b***ered up theirs to make the pointless 0-4-0 starter loco (why didn't they just produce a cheapo chassis to fit the existing mouldings (R1 and shunter). This ill-judged expensive manoeuvre must have been one of the final nails in the coffin...

 

The Bo-Bo diesel has a modified chassis to cure the problems which led to the withdrawal of the 2 rail version.

 

The R1 and 4MT tanks are basically the same as the Dublo version apart from modifications for the couplings and the removal of the 'slow running' magnetic shunt and filling in of the hole in the bunker for adjusting it.

 

The N2 tank has a modified rear fixing (a slot in the bunker to take a lug on a plate, which in turn fits onto the rear of the R1 chassis) and a different pony truck. Both these parts are hard to find and tend to be expensive.

 

The Wrenn Coronation block I have is fitted to a Dublo body, but has rather square edges (does the Dublo City?) unlike the other Dublo chassis.

 

Wrenn 'dark' green tends to be rather insipid and their undernourished commutators were a retrograde step IMHO. (These can be fitted to Dublo chassis, but require the longer Wrenn brushes (with care, these can be cut to make two, but they do tend to split) and (ideally) brush tubes. Late Wrenn armatures are five pole.

Edited February 6, 2020 by Il Grifone

[Il Grifone]

The Wrenn wagons (I only have a few) have the last Dublo underframe with the open brakegear, modified to take the Tri-ang tension lock. A further modification was made (in the eighties?) to replace the axle hangers with a plastic (delrin?) insert for pin-point axles, which produce a very free running vehicle. (These are still available as spares on eBay or direct from the seller.)

 

Loads of P.O wagon liveries (most of which are fake I think) were produced. I'll leave them to collectors of such things. I obtained a couple of 'Fisons' PRESTWINs with damaged walkways. I obtained spares for the latter and the paper Fisons labels fell off by themselves    . I put them away somewhere safe, though they are a bit tatty. New ones are available but I don't think I'll bother.

 

AFAIK Wrenn horse boxes do not include the horse. A couple came up on eBay recently for around a tenner  (not excessive for the horse, which is usually more than either the wagon or the Dublo Dinky trailer). SWMBO immediately put a stop to my thoughts of acquiring one!  Should one remove the moulding pip on the animal's rump or leave well alone?

Reproduction parts are available in a choice of colours (black, white and two shades of brown. I read somewhere that the the horses supplied with the Dublo Dinky horse box were a different shade of brown compared to the railway version (otherwise the same of course). Whether this is true or not (I suspect it's merely different batches of mouldings) I couldn't say. The horse that came with my wagon has long since gone 'walkabout'....

 

The Wrenn tank wagons are a plastic moulding, which replaced the the last surviving tinplate models.

Edited July 2, 2020 by Il Grifone

[Il Grifone]

Sorry for the Third post but they are separate subjects!

 

The 3 rail Bo-Bo diesel has traction tyres on one axle (it does tend to rock as a result and become prone to derailment. Why they didn't just copy everyone else and give the insulated side of the power bogie the tyres (one per axle) and pickup from the other rail on the trailing bogie I don't know.

 

The Wrenn version uses the same casting for both bogies (to save casting variants or to avoid using a large lump of lead? or both?).

[gtis]

1 hour ago, Il Grifone said:

Sorry for the Third post but they are separate subjects!

 

The 3 rail Bo-Bo diesel has traction tyres on one axle (it does tend to rock as a result and become prone to derailment. Why they didn't just copy everyone else and give the insulated side of the power bogie the tyres (one per axle) and pickup from the other rail on the trailing bogie I don't know.

 

The Wrenn version uses the same casting for both bogies (to save casting variants or to avoid using a large lump of lead? or both?).

Hi 

I have 2 bo-bo 3 rail locos and I haven’t 

had any derailments

Neil

[Nearholmer]

This is all really useful stuff, so thank you.

 

What I'm understanding is that, if I were to assemble a small fleet (which I don't intend to, really, honestly .......... well, maybe ....) then the 2-rail ones to aim for are:

 

EE 350hp - Wrenn

EE 1000hp -Wrenn

R1 - The Dublo one i've got on loan seems excellent, and I'm on an option to buy with that .......

N2 - Dublo

2-6-4T - Dublo (to get the adjustment screw)

 

Does that seem about right?

 

I've never been much into big locos, so they are of less interest to me (mind you, A 'Silver King' with 2R mech would get me back to my very first train set, which was actually 3R of course).

 

Kevin

[Il Grifone]

It's not that the Bo-Bos are particularly prone to derailment, It's just that the power bogie can wind itself up.

 

The 2-6-4Ts run perfectly well without the screw adjustment. (It's a rectangle of steel that fits across the rear of the pole pieces and a screw through the rear of the block fits into a tapped hole in the centre. A bent piece of phosphor bronze keeps it secure.) With the introduction of the 2 rail version (80033), they replaced the rather shapeless chimney with a much improved separate casting. This is still available, but its price has risen from £3 to £5 recently. There is a rare (read expensive) 3 rail version (80059) which always seems to have crooked transfers. 80033 and 80059 have the 'ferret' emblem.

 

The 2 rail N2 is 69550 and just the same as the 3 rail version which remained 69567, but gained nickel plated wheels and the 'ferret'. Late examples have the large oil retaining bearing and required the already oversize base for the safety valves to be made huge. Wrenn did nothing about this (obviously), but with the R1 chassis it's unnecessary.

 

The 2 rail Dublo A4 was Golden Fleece with a double chimney introduced with the 3 rail Mallard. As well as the double chimney she gained an unsightly slot in the smokebox door (for a headboard). There is no reason why a 2 rail chassis can't be fitted to a Silver King body or even a Sir Nigel Gresley.

 

Early BR livery 3 rail locomotives (1953/4) have a gloss finish. All others are matt.

Edited July 2, 2020 by Il Grifone

[Nearholmer]

Doesn’t the adjustment screw on the 2-6-4T change the magnetic characteristic to optimise either for slow or faster operation? That might suit me, because I like slooow.

[Coppercap]

3 minutes ago, Nearholmer said:

Doesn’t the adjustment screw on the 2-6-4T change the magnetic characteristic to optimise either for slow or faster operation? That might suit me, because I like slooow.

I've read that it only has effect when using controllers of the time. When using modern controllers, adjusting the screw has no effect (and it certainly didn't with my two).

[sagaguy]

11 minutes ago, Nearholmer said:

Doesn’t the adjustment screw on the 2-6-4T change the magnetic characteristic to optimise either for slow or faster operation? That might suit me, because I like slooow.

No,it was for controllers of the time, not needed now.With modern feedback controllers ,slow running can be achieved. 

 

        Ray. 

 

[roythebus]

6 hours ago, Il Grifone said:

The Wrenn wagons (I only have a few) have the last Dublo underframe with the open brakegear, modified to take the Tri-ang tension lock*. A further modification was made (in the eighties?) to replace the axle hangers with a plastic (delrin?) insert for pin-point axles, which produce a very free running vehicle. (These are still available as spares on eBay or direct from the seller.)

 

Loads of P.O wagon liveries (most of which are fake I think) were produced. I'll leave them to collectors of such things. I obtained a couple of 'Fisons' PRESTWINs with damaged walkways. I obtained spares for the latter and the paper Fisons labels fell off by themselves    . I put them away somewhere safe, though they are a bit tatty. New ones are available but I don't think I'll bother.

 

AFAIK wrenn horse boxes do not include the horse. A coupl came up on eBay recently for around a tenner  (not excessive for the horse, which is usually more than either the wagon or the Dublo Dinky trailer). SWMBO immediately put a stop to my thoughts of acquiring one!  Should one remove the moulding pip on the animal's rump or leave well alone?

Reproduction parts are available in a choice of colours (black, white and two shades of brown. I read somewhere that the the horses supplied with the Dublo Dinky horse box were a different shade of brown compared to the railway version (otherwise the same of course). Whether this is true or not (I suspect it's merely different batches of mouldings) I couldn't say. The horse that came with my wagon has long since gone 'walkabout'....

 

The Wrenn tank wagons are a plastic moulding, which replaced the the last surviving tinplate models.

Was your horse called Shergar by chance?

 

[Coppercap]

39 minutes ago, Il Grifone said:

There is a rare (read expensive) 3 rail version (80059) which always seems to have crooked transfers. 

That was from when cock-eyed Mrs Biggins was employed on the production line. Her husband was a personal friend of Frank Hornby, and he gave her a 'job for life' after she lost her husband in the trenches. She was getting on a bit when 80059 was being produced. She eventually left in 1964...

[roythebus]

I had several Bo-Bo back in the 1960s and 70s and never had a problem with derailments.

 

I have a Wrenn R1, the motor and gears have a much quieter whine than the Dublo green one I have. I'm sure the motors are different.

 

I think you'll find the 2-6-4T magnet screw is a Meccano screw.

[Butler Henderson]

7 hours ago, Il Grifone said:

The Wrenn wagons (I only have a few) have the last Dublo underframe with the open brakegear, modified to take the Tri-ang tension lock*. A further modification was made (in the eighties?) to replace the axle hangers with a plastic (delrin?) insert for pin-point axles, which produce a very free running vehicle. (These are still available as spares on eBay or direct from the seller.)

Sure they modified the wagons to allow for the plastic insert so its not possible to fit them to earlier wagons. Does anyone make the metal axle hangers.

[Il Grifone]

It's a magnetic shunt that basically reduces the flux though the armature so the motor runs more slowly (rather like the effect of a duff magnet). Unfortunately it also loses tractive effort. This was coupled with a new lower gear ratio (18:1 rather than 15:1). Since the wheel size is the same as the two Pacifics, the top speed is similar at around 100mph.

 

As I said before, I've removed it from mine*. I've a couple of sets of bits (somewhere). A H & M Powermaster with Vari-wave will make them go as slowly as required.

 

*Most of mine have been built from parts so never had the thing. The couple that had it don't any more. My original 1954 Xmas present lost it a long time ago. It must be about the time I converted her to 2 rail in the early sixties. She is 3 rail again now.   'New' wheels -tThe originals were the subject of a failed EM conversion - Two I turned down nicely, but the third I overdid....

 

The screw is a blackened 6BA cheesehead (6BA IIRC), but the body fixing screw is Meccano (part 111 something - I can't remember whether ½" or ⅝", but I think either would do).

 

The 4MT bodies often have a rubbing mark through the number from the cardboard packing. This can even be present on 'mint' examples   caveat emptor!

 

I don't think there is any difference between Wrenn and Dublo ½" motors. Any difference in performance is probably due to production tolerances.

 

I don't know of anyone making the metal tags, but them come up on eBay from time to time, but usually at a price that makes it cheaper to reclaim them from scrap wagons yourself. These can often be obtained from toy fairs very cheaply. A pound or so from the bargain box under the stall.

 

My horse disappeared long before Shergar was even thought of! 

 

 

Edited February 6, 2020 by Il Grifone
Keyboard finger trouble

[dcordingley]

Not sure if this has been mentioned, but a few years ago somebody in the Hornby Railway Collectors' Association (HRCA - recommended to all those interested in things Hornby or Hornby Dublo) pointed out to me that the Wrenn diesel shunter had flanged centre driving wheels, unlike the HD flangeless version. I have a Wrenn shunter converted to 3 rail running on my 3 rail layout, and it certainly has the flanges....

 

David   

[Il Grifone]

I'm not sure about mine and she's about 1000 miles away at the moment so a bit too far to check.

[Nearholmer]

1 hour ago, Il Grifone said:

It's a magnetic shunt that basically reduces the flux though the armature so the motor runs more slowly (rather like the effect of a duff magnet)

I think it will be the other way round.

 

A weak flux requires the motor (and hence the model loco) to run faster to generate sufficient back e.m.f. to cancel-out the supply voltage.
 

A permanent magnet motor with a weak magnet (either the permanent magnet or the wound field magnet that is the armature) will classically run fast, but with low torque, and the same effect is used on a real d.c. motor train to achieve high-speed running - in that case sections of field winding are progressively switched out of circuit to increase speed (known as ‘weak field notches).

 

’Shunting’ has several different meanings in the context of dc motors, but here I think it is being used to mean shunting the magnetic circuit so as to divert some of the flux into a path that causes it not to contribute to the action of the motor ..... to waste flux effectively.

 

Anyway, I think I can see what the idea is, and why it would be unnecessary with a modern controller which can provide a very wide, and finely graduated, range of effective (rms) voltages.

[Il Grifone]

Something I've pondered myself! (It's a long time since I studied electrical engineering.)

The Dublo device slows the motor when wound in to touch the magnet and runs normally when screwed out and a weak magnet also results in slow running. I think the mechanism is that the weak field generates less back e.m.f.  resulting in a higher current which in turn lowers the voltage due to the resistance of the supply circuit. Too weak a field and overheating occurs. Low torque will only increase the effect due to frictional losses.

 

A real train's electrical supply has a very low source resistance and will be designed for the higher current.

Edited February 6, 2020 by Il Grifone