Stanier Class 4MT - poor pickup design - beware!

[NERBOB]

Hornby (China) R3021 - Stanier 4MT 42613 - DCC ready.

 

Oh dear, Oh dear...............was not expecting this at all. Bear with me as I'd like to tell the whole story!

 

Now, before anyone at Hornby, UK or in China, jumps up and down with injured pride (!), this post is not meant to criticise, more to help both customer and manufacturer understand this particular difficulty. (and I hope a representative at Hornby will look at this post??)

 

After a full day of pondering over a problem, testing with both DCC and DC, I discovered that a poor design (VERY poor design) caused, in the end, a full rewire of the Locomotive with the need for some additional cabling.

 

There is absolutely nothing wrong with the aesthetics of this Locomotive and I would encourage its purchase as it really is a lovely model (I now have two).

Number 1 was fitted with lights, firebox flicker, and a standard (non sound) DCC decoder. All works as planned, and runs beautifully.

 

Number 2 was fitted with lights, firebox flicker, and a Sound Decoder (ESU). All wired up as before, and off we go! All working fine - for a while.

 

The Loco kept stopping for no apparent reason. All functions / Lights / Sound / Speed, DEAD. 

If you're into fault-finding, great. If not, how very disappointing it would be to run home with your purchase, fit it up with your Decoder and this happen - and you don't possess anything other than a screwdriver to take the body off. This is how it should be for the majority - working straight from the box...................but

 

Those of you (us) who are a little more experienced and with a toolbox full of a lifetime's collection of specialist tools and a cosy workshop to work in would find a great deal of satisfaction in stripping down a Locomotive and putting it all back together again.

However for those of us, who are able to fault find on a piece of equipment, know how frustrating it is to go through countless fault finding procedures and not find the answer at the end of it.

 

This I did - decoder in and out, functions checked and rechecked, CVs examined, checked and rechecked, physical testing with voltmeter, soldering iron, cables on and off, visual checks and following cable routes etc..........the process goes on and on.

 

Oh well, the next day I decide to look into a re-wire of the Loco's motor and pickup connections after measuring a voltage 'drop' and 'power outage' which was completely random.

 

Putting the decoder to one side, satisfied that it was working correctly (I tested it in another Loco - Diesel as it happens, but the functions were all ok) a strip-down of the 4MT was decided upon - what will I find? A faulty soldered joint? A faulty connection? A chafing wire?

 

NO.......................a poor design problem!

 

Taking the keeper plate off the bottom of the chassis to expose the phosphor bronze pick-ups, I find a formed piece of brass/phosphor bronze which acts as pick-up for the left and right side of the wheel set. Nothing unusual about this except that there is NO physical connection between pick-ups and cable/chassis. Thie connection is wholly reliant on pressure of the keeper plate to press the pick-ups onto a "dumb post" for the chassis and a brass ferrule for the insulated pick-up.

 

These had failed, miserably, and intermittently, on this particular model, so as to fail in guaranteed pick-up of current from the rails, hence the Loco simply stopped.

 

The debicle of a design flaw is in the reliance, simply of pressure from the keeper plate rather than have a guaranteed soldered connection to the insulated side and a guaranteed crimp to the chassis.

 

Remember that I have 50+ years of experience of Hornby's products, and have a professional workshop, so this wasn't a particularly "big issue" to me, although the full day of fault finding gets very tiresome when there are new "obstacles" (DCC & decoders) in the mix, and when I couldn't see the simple problem!

 

Remedy:

To fully rewire the Locomotive, and in addition, provide a soldered connection to the insulated side, and a properly crimped connection to the chassis side of the wheelsets. As a result, to rewire the Decoder blanking plate, test and prove DC control, followed by a complete rewire to the decoder (customer demarkation points - 8 wire connector plate).

 

Lessons:

If in doubt - send it back - all of it!

Do not tamper with a Decoder - send it back!

Do not attept any repair/fault finding exercise if you do not have the tools & experience to do it!

 

If you wish to consult me on this, then please do so (no charge!), but I recommend sending the product back if you're not happy with it.

Please see Pictures below.

Best Wishes,

Robert

 

Photos here show the issue (keeper plate removed).

1) Shows Brass ferrule with pick-up lifted from contact

2) Shows Dumb Post on chassis with pick-up lifted from contact

3) shows wires linking pick-ups. This needs to be routed up through the chassis and terminated at the decoder blanking plug's socket.

 

[robmcg]

R3021 was not fitted with a decoder, nor sound, nor firebox flicker by Hornby.

 

The problems may arise from whomever made these mods. Factory DCC models may have better pickups, I don't know, but the mods would require more current than a simple DCC-ready engine requires.  The 'poor design' was done without necessarily allowing for such as sound and firebox flicker .

 

The person who added these features should perhaps have modified/improved the design to suit the additions?

[mark axlecounter]

Hi Robert I two have a few stainer tanks what I have put sound in and like you have had a problem with pick ups on all of them (dc and Dcc ) I had took the chips out messed around and still they stalled. I found on mine that the pickups were moving when the wheels came in contact with them. The method I used was piece of paper folded over and placed over the pickups then put the Keeper plate over.

I can now say that the locos have been sorted I know a few people who have had a issue with pickups on there 2-6-4 tanks they have done the mod and it's cured it

Hope your loco is ok

Mark

[black and decker boy]

R3021 was not fitted with a decoder, nor sound, nor firebox flicker by Hornby.

 

The problems may arise from whomever made these mods. Factory DCC models may have better pickups, I don't know, but the mods would require more current than a simple DCC-ready engine requires.  The 'poor design' was done without necessarily allowing for such as sound and firebox flicker .

 

The person who added these features should perhaps have modified/improved the design to suit the additions?

 If the loco is DCC ready then it is sold equipeed for the consumer to just drop in the DCC chip. DCC sound is the very same thing and the other bits attach to the chip & DCC board too so are also part and parcel of what the loco is sold 'ready' to do. I don't think any manufacturer says you have to rebuild the electrical side of a DCC Ready model in order to run DCC. The only difference between a DCC ready and DCC fitted loco from Hornby will be the installation of a DCC chip by the factory.

 

Fitting DCC chips to the pre-wired socket provided by Hornby requires no access to the chassis, pickups or wheels.

[RedgateModels]

Nothing new in this design, the loco drive 8F has used the same method since 2003 at least. It could be seen as penny pinching by the designers/accountants but it does remove one soldering operation at least and Hornby locos have used the chassis as a current path since God were a lad

 

I've had cause to remove the post and solder a second wire to the pickup when adding DCC sound, but that is because I like to use the tender pickup connector to pass the speaker wires to the tender, so needed to isolate the current pickup from the chassis.

 

Sounds like you just had a faulty loco, it happens

[toboldlygo]

The strange thing is Hornby have modified this arrangement on the Rebuilt West Country's & Battle of Britain's and they are soldered. If they sit for a while you can get oil seepage between the keeper plate and the chassis which interferes with the connection. Simple to fix - just degrease and reassemble

[34theletterbetweenB&D]

Nothing new in this design, the loco drive 8F has used the same method since 2003 at least. It could be seen as penny pinching by the designers/accountants but it does remove one soldering operation at least and Hornby locos have used the chassis as a current path since God were a lad ...

But it is a poor design for the DCC era, not least for the propensity to momentary short circuits on some examples, enough to trip a DCC system. That's how I became aware of it, when one of two new and notionally identical 8F chassis (same model, bought at the same time) exhibited this trouble. With thirty some locos on the rails, and the one that had created the momentary short that tripped the system no longer in a shorted condition, it needed running in the dark to 'spot the spark' to track it down. Hornby have dropped it on newly introduced chassis from the Britannia onwards thankfully.

 

The 'sign peculiar' of a Hornby steam chassis with a live chassis block is a wire (usually blue) from a screw securing the combined front motor clamp and worm cover, which runs to the decoder socket. Adding soldered wired connections to the pick up strips and isolating the chassis block is my preferred solution. Do this on all examples whether or not they have exhibited a problem, as insurance.

[robmcg]

 If the loco is DCC ready then it is sold equipeed for the consumer to just drop in the DCC chip. DCC sound is the very same thing and the other bits attach to the chip & DCC board too so are also part and parcel of what the loco is sold 'ready' to do. I don't think any manufacturer says you have to rebuild the electrical side of a DCC Ready model in order to run DCC. The only difference between a DCC ready and DCC fitted loco from Hornby will be the installation of a DCC chip by the factory.

 

Fitting DCC chips to the pre-wired socket provided by Hornby requires no access to the chassis, pickups or wheels.

 

Yes you are quite right. I should have thought  this through with a clear head...

[Jim49]

The same design of pick-up is used on the Black 5 as well, guess how I know! There may be other locos in Hornby's steam range with the same potential problem present, just waiting for a small knock to shift the component parts slightly, not enough movement to be obvious but just enough to no longer make firm contact and then nothing's happening.

 

Jim

[MikeParkin65]

The same design of pick-up is used on the Black 5 as well, guess how I know! There may be other locos in Hornby's steam range with the same potential problem present, just waiting for a small knock to shift the component parts slightly, not enough movement to be obvious but just enough to no longer make firm contact and then nothing's happening.

 

Jim

There certainly are more with this arrangement - I have an A4 where the contact snapped so the loco wouldn't run without the tender connected (this is the first issue A4 60031 without the wired tender connection). Investigation revealed the break although I couldnt see how it had occurred. I soldered a new pick up to touch what NERBOB aptly calls the 'dumb post' but I much prefer both his rewire or the simpler measure of jamming the contact upwards with a piece of folded paper as proposed by axelcounter. I agree overall that this Hornby method of pick up isn't brilliant and am glad if it has been replaced on newer models.

[Crewlisle]

Hornby (China) R3021 - Stanier 4MT 42613 - DCC ready.

 

Oh dear, Oh dear...............was not expecting this at all. Bear with me as I'd like to tell the whole story!

 

Now, before anyone at Hornby, UK or in China, jumps up and down with injured pride (!), this post is not meant to criticise, more to help both customer and manufacturer understand this particular difficulty. (and I hope a representative at Hornby will look at this post??)

 

After a full day of pondering over a problem, testing with both DCC and DC, I discovered that a poor design (VERY poor design) caused, in the end, a full rewire of the Locomotive with the need for some additional cabling.

 

There is absolutely nothing wrong with the aesthetics of this Locomotive and I would encourage its purchase as it really is a lovely model (I now have two).

Number 1 was fitted with lights, firebox flicker, and a standard (non sound) DCC decoder. All works as planned, and runs beautifully.

 

Number 2 was fitted with lights, firebox flicker, and a Sound Decoder (ESU). All wired up as before, and off we go! All working fine - for a while.

 

The Loco kept stopping for no apparent reason. All functions / Lights / Sound / Speed, DEAD. 

If you're into fault-finding, great. If not, how very disappointing it would be to run home with your purchase, fit it up with your Decoder and this happen - and you don't possess anything other than a screwdriver to take the body off. This is how it should be for the majority - working straight from the box...................but

 

Those of you (us) who are a little more experienced and with a toolbox full of a lifetime's collection of specialist tools and a cosy workshop to work in would find a great deal of satisfaction in stripping down a Locomotive and putting it all back together again.

However for those of us, who are able to fault find on a piece of equipment, know how frustrating it is to go through countless fault finding procedures and not find the answer at the end of it.

 

This I did - decoder in and out, functions checked and rechecked, CVs examined, checked and rechecked, physical testing with voltmeter, soldering iron, cables on and off, visual checks and following cable routes etc..........the process goes on and on.

 

Oh well, the next day I decide to look into a re-wire of the Loco's motor and pickup connections after measuring a voltage 'drop' and 'power outage' which was completely random.

 

Putting the decoder to one side, satisfied that it was working correctly (I tested it in another Loco - Diesel as it happens, but the functions were all ok) a strip-down of the 4MT was decided upon - what will I find? A faulty soldered joint? A faulty connection? A chafing wire?

 

NO.......................a poor design problem!

 

Taking the keeper plate off the bottom of the chassis to expose the phosphor bronze pick-ups, I find a formed piece of brass/phosphor bronze which acts as pick-up for the left and right side of the wheel set. Nothing unusual about this except that there is NO physical connection between pick-ups and cable/chassis. Thie connection is wholly reliant on pressure of the keeper plate to press the pick-ups onto a "dumb post" for the chassis and a brass ferrule for the insulated pick-up.

 

These had failed, miserably, and intermittently, on this particular model, so as to fail in guaranteed pick-up of current from the rails, hence the Loco simply stopped.

 

The debicle of a design flaw is in the reliance, simply of pressure from the keeper plate rather than have a guaranteed soldered connection to the insulated side and a guaranteed crimp to the chassis.

 

Remember that I have 50+ years of experience of Hornby's products, and have a professional workshop, so this wasn't a particularly "big issue" to me, although the full day of fault finding gets very tiresome when there are new "obstacles" (DCC & decoders) in the mix, and when I couldn't see the simple problem!

 

Remedy:

To fully rewire the Locomotive, and in addition, provide a soldered connection to the insulated side, and a properly crimped connection to the chassis side of the wheelsets. As a result, to rewire the Decoder blanking plate, test and prove DC control, followed by a complete rewire to the decoder (customer demarkation points - 8 wire connector plate).

 

Lessons:

If in doubt - send it back - all of it!

Do not tamper with a Decoder - send it back!

Do not attept any repair/fault finding exercise if you do not have the tools & experience to do it!

 

If you wish to consult me on this, then please do so (no charge!), but I recommend sending the product back if you're not happy with it.

Please see Pictures below.

Best Wishes,

Robert

 

Photos here show the issue (keeper plate removed).

1) Shows Brass ferrule with pick-up lifted from contact

2) Shows Dumb Post on chassis with pick-up lifted from contact

3) shows wires linking pick-ups. This needs to be routed up through the chassis and terminated at the decoder blanking plug's socket.

 

4MT 1.jpg4MT 2.jpg4MT 3.JPG

 

 

I have just come across the same problem with my Hornby Stanier Class 5 (product reference number unknown but was purchased in 2006).  My layout has been dismantled in the spare bedroom for about 18 months.  It had been running for many years fitted with a sound decoder.  I have been doing a few mods to the loco (not the decoder) and when I came to give it a test run it was dead.  First I suspected one of the decoder wires had come adrift during removal/fitting the loco body.  But after a gentle tug on each wire all were OK.

 

I then remembered I had a similar problem with my Hornby Princess a few years ago which turned out to be the contact between the chassis and one side of the wheel pick ups.  Once more it was the poorly designed chassis spigot (see original photo) and the wheel pick ups. 

 

Not wanting to do a complete rewire job like NERBOB, I decide on a simpler way.  I carefully removed the plastic keeper plate on the bottom of the chassis holding the pick ups in position and removed the chassis pick up.  The bottom piece of plastic providing the insulation between the pick ups and the chassis appeared to be about 0.25mm thicker than the length of the chassis spigot thus not making electrical contact when assembled.  The pick ups are located by small lugs moulded on the plastic so I measured the centre of the chassis spigot from the edge of the chassis and made a depression in the thin copper tab on the pick ups at this centre with a small pozidrive screwdriver (like immitation rivetting).  I then carefully deposited a small blob of solder on the reverse side to make up for the 0.25mm difference between the length of the spigot and thickness of the plastic.

 

Loco was reassembled and everything worked OK.  Make sure that the centre screw on the keeper plate is tightened first to ensure maximum pressure on the spigot.

 

[Crewlisle]

Further to my comment No. 11, I have just remembered that I had not run my Black 5 without the tender prior to buying a DCC Concepts Rolling Road 2 years ago.  My Black 5 probably has had a pick up problem ever since I bought it!  Because it had always been run with the tender attached (complete with tender pick ups) is the reason that it had not been a problem before.  How many of you own Hornby tender locos (with pick ups) where there has always been a problem with the loco chassis pick up design problem?

[Barry O]

This "problem" is a production engineering problem - and it is quite common place across a variety of locos from China of whatever manufacturer.

 

I have just re-wheeled a Hornby 2-6-4T and added some wires connecting motor to pickups. The Bachmann 2-6-4T (Fairburn) has two wires to the pickups but mine were so short I have had to unsolder them.

 

However - before you start testing chips etc its always worth while trying the loco on dc as it can pinpoint electrical pick up faults quicker...

[34theletterbetweenB&D]

Full support for getting the mechanism right on DC before 'overlaying' a decoder. My recent Hornby purchase was a B17, perforce purchased in 'DCC fitted' form as that was what was available. Turned out to be mechanically and electrically fine; still to the best standard Hornby were achieving while with Sanda Kan. But I had to remove the supplied decoder to determine that : the decoder actually degraded the performance from what the mechanism alone could deliver on DC.

 

The most sensitive test ahead of decoder fitting, once the loco is running mechanically smoothly with no binds of any sort in evidence, is a dead slow creep on 'vanilla' DC (no feedback assistance). It has to keep going smoothly. If there is any stuttering or momentary change of speed, or evidence of lights flickering where fitted, it is a sure thing that current collection has been significantly interrupted. Got to fix that before the decoder goes in, because the decoder effectively amplifies the effect of loss of track supply.

 

Conversely, if the loco can maintain pick up adequately with a small DC supply voltage on the track, then pick up is likely to be very robust with the permanent higher voltage DCC supply. Which is what we want.

[hallmodelspares]

I had many problems with following Hornby engines ex Dapol castle, Super detail loco drive A4,a3 and Duchess.

Mostly these involved the pickups on the loco not being very good. i found by gently bending the wheel contacts out

this solved the problem.

[toboldlygo]

Not actually got an issue with one of these, however have got one to renumber, recrest etc. Just need to know where to find info on the class...

[34theletterbetweenB&D]

If you need BR period allocations of locos to pick a number for the area you are interested in, this may prove useful. http://web.archive.org/web/20070625232926/http://www.users.globalnet.co.uk/~luigin/Locoshed/Locoshed.htm

 

The number range for the standard two cylinder with separate dome and top feed is 42425 - 42494, 42538, 42545 - 42672. The gap in the number series is largely filled by the three cylinder type, and the few domeless boilered members of the two cylinder class.

[Bill Conroy]

My Duchess of Southerland tender drive is very intermittent and it only has a single spring pick up on the front driving wheel if this is held down the train runs otherwise zilch. I find it hard to understand why every wheel on one side does not have pick up's to ensure constant motion but a single wheel is asking for disaster. Can anyone suggest how to add additional pick ups before I move to DCC.

[Brit70053]

Hello Bill and welcome to RMWeb, not sure if I can answer your query directly, but I'm certain someone on here will come up with an answer .

 

May I ask if your Tender drive Duchess was bought 'new' by you or was it second hand?  I had a 'ahem' pre-owned one of these many moons ago and seem to recall that pick ups were present on at least the front and rear driving wheels on one side of the loco chassis. There was also an arrangement where light was passed through a transparent plastic insert to shine from 'lamps' on the buffer beam. Is this the same as your Loco?

 

Have a look at the sprung pick up and its retainer which is present on your model, then look near the other wheels on the same side to see if there are further retainers which either are missing a pick up, or whether there are pick ups which have been distorted or broken so that they are no longer effective.

 

Establishing 'what should be there' will be your first step to resolving the problem.

 

Regards,

 

                John

[sparaxis]

Hornby is (was) not alone in this dumb design. Several Roco locomotives have used similar design where power is transferred from the keeper plate to the PC board by means of vertical pins. My class 93 tank has worked fine from day one but my sound equipped 03.10 only picked up from the tender and one side of the loco. The tab on the pickup strip that was supposed to be bent up to meet the pin was flat. A bit of bending fixed that. The only consolation is that the contact strip was long enough and springy enough that good contact resulted. 

 

I can understand why they do it though..I have had to deal with a few locos with short wires from keeper plate to pc board that have been a devil to work with - and it is not alway convenient to de-solder the wires. It all depends on the layout of the loco interior.

 

Luckily all my Hornby locos afflicted by this dumb design have worked ok until now.

 

I am a firm believer in having as many pickups as possible, and add them to bogies and tenders by using a square of PC board and thin phosphor bronze wires shaped to fit. Does wonders for slow speed running on dodgy track and pretty much essential for reliable DCC operation.

 

It is extremely irritating to spend a fortune on a loco then to have to fiddle with it because the pickups are defective or otherwise insufficient.

[JSpencer]

My Duchess of Southerland tender drive is very intermittent and it only has a single spring pick up on the front driving wheel if this is held down the train runs otherwise zilch. I find it hard to understand why every wheel on one side does not have pick up's to ensure constant motion but a single wheel is asking for disaster. Can anyone suggest how to add additional pick ups before I move to DCC.

 

The duchess of Sutherland you quote is from the late 1970s. This particular Duchess has working from lamps (2 to be precise) that was dropped on later Duchesses.

 

This loco does not use pickups per-se except for the singular one you noticed - which I will come back to later.

 

The driving wheels (not actually driven on the model but they are on the real thing) have steel axles. There are plastic bushes on one side where axle joins the wheel.

The other side is not isolated, with the metal axle in contact with the metal wheel. The metal chassis block in the loco part, is live. The rear pony (not actually a pony on the real loco per-se) is metal and is screwed into the chassis block by a brass screw. It is pushed against the head of the screw by a spring. Finally their is a hole in the Diecast part of the pony truck, where the tender pin slides into it. An additional brass clip of the pony ensures electrical contact with the tender pin.

 

Basically electricity is picked up by the wheels, runs through the axles, into the chassis block, then the pony, the brass clip and into the tender pin.

 

A wire runs from the tender pin to one side of the motor. A second wire runs from the other side of the motor to the live metal tender chassis block, and again the tender wheels are attached to steel axles, one side isolated by plastic the other side live.

Thus electricity is picked up by the loco on one side of the rails and returned by the other.

 

After over 3 decades, oxides and dirt build between the joints in the system (the motor ages too and the magnet gets weaker). The whole set up becomes jerky. Locos that have been run on regular basis since 30 years might avoid that (electricity can stop oxidation in its tracks), but may suffer from wear and tear.

Cleaning and revamping the lot can cure this although you may find certain parts need replacing (I replaced a pony on an aging Mallard once which temporary cured the problem).

Do not add oils as these can isolate things too.

 

Now the single wiper you have seen, is actually for the lighting system. It takes electricity from the live loco chassis and returns it to the rails via the single wiper.

[JSpencer]

The current Hornby pickup system of wipers not connected anywhere have worked fine in my experience.

 

They do bend out of the way over time, but the keeper plates makes them very easy to get at and to readjust when that happens.

 

Bachmann's are much harder, as you need to strip part of the chassis down before you can readjust them. Indeed a recent c class I brought had a contact problem plus the sand pipes touching the wheels both sides from time to time causing a short circuit!

[Rshakes3]

Hi All,

 

I have read this topic with interest as over the last 6 months my Hornby Mallard has developed a ‘mind of its own’. I purchased the loco 2^nd hand via the net rather that new about 18 months ago and it had run ok.

So I have cleaned the loco wheels with a little Peco wire brush and a cotton bud with a little bit of isopropyl - lots of dirt removed initially. I also ‘attacked’ the Tender wheel, this is a model with the draw bar electrical connection to the tender, not a 4 pin plug.

Following my initial read of this topic I also inspected the loco pick up wipers and placed 2 small pieces of business card under the keeper plate as discussed earlier.

Running was much improved for a time but I did find I had to keep cleaning the wheels. This model has the Brass ‘yellow’ wheels – not the Golden anniversary model – and I even purchased a set of silver/black tender wheels.

So keeping the wheels clean seems to be a key for this loco – none of my other loco’s are this sensitive and I have 2 A3 & another 3 A4s – but the loco pickups are an area of improvement for mine.

 

Now my NRM Black Flying Scotsman - R3100 – started to play up last week. I inspected the loco pickups and I found that it had twisted one of the front wipers but both Wipers were soldered to wires - factory fitted as such.

 

I`m not that confident that I can replace the damaged wiper correctly so I`ll returned it to my local model shop and have it done correctly. At that same time I`ll have the Mallard’s wipers ‘soldered’ in as well.

 

So a bit of a ramble however I too have experienced this design short coming and was a little surprised good ‘house keeping’ - as in keeping wheels clean - was not the only the only item to consider.