Kernow GWR steam rail motor

[mikesndbs]

2 hours ago, The Stationmaster said:

Simple answer - lamp cases were often grubby and GWR red painted lam cases were often criticised for being difficult to see (by Signalmen)/. Lamps weren't normally lit during daylight hours unless there was a listed tunnel through which thetrain would be running.  And, apart from the very small side light on some lamps (invisible at any sort of distance unless the lamp was burning with too big a flame) you had to be pretty near square to see the light in a properly trimmed lamp during darkness,

 

So get out the dirtying box and get to work dealing with any ridiculously bright LED head and tail lamps and making the lamps cases look more like the real things were in evertday traffic.  And obscure the LED glow at the same time.   Regrttably for thsoe unfamiliar with the light coming from oil lit head and tail lamps the LEDs used on many models give a very misleading impression

 

Yeah I absolutely get what you are saying however this has had less than five hours use and I expect the circuits to be up to the task, got it open now and am trying to trace the circuits, got a couple of missing capacitors, anyone else missing C15 and 16? PCB is double sided and the underside is hidden by the coach lighting strip. Buzzed through and I have a common via a 200 ohm resistor and both the other sides connected to track feed. There are diodes on the blanking plug which I'll check.

 

Update: Kernow said send it back but then are unhappy because I've fitted crew and passengers :(

Edited February 1 by mikesndbs
update

[Ian Hargrave]

3 hours ago, mikesndbs said:

 

Yeah I absolutely get what you are saying however this has had less than five hours use and I expect the circuits to be up to the task, got it open now and am trying to trace the circuits, got a couple of missing capacitors, anyone else missing C15 and 16? PCB is double sided and the underside is hidden by the coach lighting strip. Buzzed through and I have a common via a 200 ohm resistor and both the other sides connected to track feed. There are diodes on the blanking plug which I'll check.

 

Update: Kernow said send it back but then are unhappy because I've fitted crew and passengers :(

Your recent YouTube video showing what you think is a lighting feature of the model encouraged me to try the same 

However,it simply does not work with mine …. power off =lights off  and I cannot replicate what I see on your video.

Maybe the phenomenon is connected in some way with your present problem ?  Good luck.

[mikesndbs]

57 minutes ago, Ian Hargrave said:

Your recent YouTube video showing what you think is a lighting feature of the model encouraged me to try the same 

However,it simply does not work with mine …. power off =lights off  and I cannot replicate what I see on your video.

Maybe the phenomenon is connected in some way with your present problem ?  Good luck.

 

Oh how odd! Has anyone else noticed if C16 and 16 are missing on thiers? Kernow have agreed to take it back and sort it out for me somehow. Think I'll remove the people all the same as that gives them more flexibility, however I'd not want to lose the stay alive effect lol 

[Harlequin]

23 minutes ago, mikesndbs said:

 

Oh how odd! Has anyone else noticed if C16 and 16 are missing on thiers? Kernow have agreed to take it back and sort it out for me somehow. Think I'll remove the people all the same as that gives them more flexibility, however I'd not want to lose the stay alive effect lol 

They are not fitted on my Diag. O No.61 but I wouldn't describe them as missing.

 

Very often PCBs are design with pads for optional components and I think these are just options that have not been used in the release models.

 

[Harlequin]

My 61 is still with me and opened up to have things done inside but poor old sound-fitted 97 is winging it's way back to Kernow, I'm sorry to say. I couldn't work out what was causing her to limp and sometimes jump.

 

[didcot]

I wonder if it was the same problem as mine. The expansion link bracket on one side was being pulled back and forth. But the top part of the motion was catching on the underside of the body on curves.

I did send an email to Guildford with a video. Then I read the delivery email properly and created a returns label. Packed it up with some pictures and sent it back for exchange. It's a cracking model though and I'm sure it will be sorted with the usual Kernow efficiency. 

[melmerby]

On 01/02/2024 at 19:30, didcot said:

It's a cracking model though and I'm sure it will be sorted with the usual Kernow efficiency. 

It deserves to be as it is a really good model.

AFAIK it is also the first RTR 70' GWR vehicle.

 

BTW something that I've spotted, when new the cylinder covers were polished.

Edited February 3 by melmerby

[Ribird]

Question, as I've not seen it mentioned, what is the 47 on either end of the railmotor? Seems it is only on the two chocolate/cream versions. I've attached a photo of mine, which seems to have a piece of dust on the inside of the driver windows. 

[Pteremy]

9 hours ago, Ribird said:

Question, as I've not seen it mentioned, what is the 47 on either end of the railmotor? Seems it is only on the two chocolate/cream versions. I've attached a photo of mine, which seems to have a piece of dust on the inside of the driver windows. 

 

Is it the weight? You can see the coach weights - as simple numerals - painted on the ends of GWR coaches in the 1930's and in BR days, but i don't know when they first started doing this.

[Miss Prism]

I think the numerals are cast ones. Don't know when they first appeared - is it a Collett-ism? By Hawksworth days, they had a thin backing plate.

 

 

[mikesndbs]

On 01/02/2024 at 13:10, mikesndbs said:

OH NO, I was just making a feature video of my railmotor when I noticed the tail lights are now super bright, madly so. And the front lights are now both dead Grrrrrr Just when I was well in love lol.

Clearly some kind of diode or switching transistor failure and I bet the tail/reds will fail soon.

 

Why do there always have to be these ruddy problems :(

 

Just incase this is of interest to anyone or maybe there are some good electronic techs looking in, here is what i found before sending back together with some observations made to Kernow.

 

I’ve done extensive and careful tests and examinations of the tail/head lighting circuit on the model and can almost certainly say that the white LED section has failed.

I note that the voltage from the landing pads on top of the PCB (3v) switches between + at pin 1 to pin 2 or 3 depending on direction.

The LEDs are protected by 6k8 resistors in the roof pcb which should have been fine.

 

Due to the SMC I can’t test properly but I cannot find any defect on the main PCB however given the failure there must be something amiss.

 

All I did note was that C5 appears to be the only protection across the motor/supply feeds on the pcb and that is just 0.03NF which is incredibly small.

Given the coreless motor and likely back EMF from it I do wonder if this possible spike might be the cause.

If something line 0.1uF was across the supply and particularly the LED supply this might provide a more robust degree of protection.

0.1uf across the dcc blanking plug would provide protection for the model as well as making it easy for those fitting dcc to remove it.

 

I note there are diodes D3 and 4 if diodes were across the LEDs in reverse this might also provide protection against any transient spikes.

[K14]

2 hours ago, Miss Prism said:

I think the numerals are cast ones. Don't know when they first appeared - is it a Collett-ism? By Hawksworth days, they had a thin backing plate.

 

 

 

Sometime during the Lake era was the best I came up with - probably post WW1. They're cast iron & screwed direct onto the panels - I've never seen any with a backing plate.

 

Pete S.

[The Stationmaster]

3 hours ago, Pteremy said:

 

Is it the weight? You can see the coach weights - as simple numerals - painted on the ends of GWR coaches in the 1930's and in BR days, but i don't know when they first started doing this.

They definitely appear to be weights.  They were first applied during 1926 (possibly even very late 1925 as vehicles were shopped??) and were officially brought into use from 03 January 1927 when the GWR introduced a new system for calculating the loads of passenger etc trains.  They should be at diagonally opposite corners of the vehicle ends and were orignally painted (and still seem to have been still been painted onsome vehicles at much later dates.

 

On Yellow Spot coaching stock photos indicate that the yellow spot was painted immediately next to the tare weight figure on the side nearer to the outer edge of the vehicle bodywork.

[DLT]

I saw one of these "in the flecs" the other day, absolutely superb!

[Miss Prism]

1 hour ago, K14 said:

I've never seen any with a backing plate.

 

I was looking at the pics of W6265W (page 100) and W251W (page 124) of Harris 2nd edition, but most of the preserved examples do seem to be just numerals (followed by a strange yellow circle).

 

Edited February 2 by Miss Prism
251, not 252

[The Stationmaster]

14 minutes ago, Miss Prism said:

 

I was looking at the pics of W6265W (page 100) and W251W (page 124) of Harris 2nd edition, but most of the preserved examples do seem to be just numerals (followed by a strange yellow circle).

 

The 'strange yellow circle' is the yellow spot I referred to above - officially referred to as 'YELLOW disc'.  Nothing strange about it at all - it was applied from 1937 (first published reference is dated 12/37) to 'new coaches being built to cross -country dimensions'.  Vehicles so branded were allowed to work over all LMS main lines and various secondary routes etc; without restriction to the LNER; and on various specified SR routes.   It is mentioned in the 1947 coach livery diagram in 'Great western way' but that does not appear to quote the date of its introduction.  Yellow disc marking might later have been applied to some earlier vehicles?; it was also applied to Hawksworth passenger carrying stock except the 12 wheel sleeping cars.

 

In some respects it was almost an opposite of vehicles branded with a Red Triangle which were not permitted to be worked off GWR lines at all (and in many cases were subject to restrictions, of varying severity depending on the vehicle length and width, within GWR territory).   The marking does not appera to have been carried by steam raoilmotors but might not show on the type of film.  The Red Triang/e marki would seem to have been introduced at some time between 1924 and 1935/6.

[melmerby]

2 hours ago, mikesndbs said:

All I did note was that C5 appears to be the only protection across the motor/supply feeds on the pcb and that is just 0.03NF which is incredibly small.

Given the coreless motor and likely back EMF from it I do wonder if this possible spike might be the cause.

That's for suppression, a legal requirement.

 

[K14]

35 minutes ago, Miss Prism said:

 

I was looking at the pics of W6265W (page 100) and W251W (page 124) of Harris 2nd edition, but most of the preserved examples do seem to be just numerals (followed by a strange yellow circle).

 

 

Not on W251 (but note painted dimensions data panel):—

 

 

W6265W:—

 

I agree that there's something going on with the disc, but not with the numbers.

 

Single numbers make more sense to me than bespoke plates as it's just simpler. The GW were "penny conscious" so sending an order to the foundry for a couple of buckets of twos & zeros would be less wasteful.

 

The Strange Yellow Circle is a route restriction symbol. Details as per @The Stationmaster's post. Centenary & Ocean Saloons at 9'-3" were Red Triangle & restricted to a very few routes. The examples I've seen were all cast (without a backing plate) & held on by three countersunk screws.

 

Pete S.

 

 

[Dragonfly]

Well, mine arrived on Wednesday, and now stretching it's legs on one of Stafford's layouts.

 

Spectacular work from Kernow, as ever!

[97403_Ixion]

10 hours ago, mikesndbs said:

...

I note there are diodes D3 and 4 if diodes were across the LEDs in reverse this might also provide protection against any transient spikes.

I've not had time to fully read the thread but noted you mentioned diodes in reverse across the LEDs...

 

If I read this right, I suspect this has been done to limit the reverse voltage the LED sees during back-emf surges.  Some LEDs have breakdown voltages in the order of just 5V in reverse (the forward voltage depends on the colour - for very electronic reasons!).  Back emf voltages may be significantly higher, especially if there is nowhere for the inductively driven current to go.  Consequently, an LED could take the 'hit' if the surrounding circuit does not prevent it from happening in the first place.  This 'hit' could well cause damage to the device - the higher the voltage, the more power dissipating damage it can cause.

 

Now, please NOTE that I am not saying the manufacturer has in any way used a poor circuit... in fact it sounds like quite the opposite if I understood the observation right and it was for this reason and certainly one I applaud!  I just offer the above comments to help people understand a possible cause for LEDs failing (in any model...), though this may not be the cause of any issues people may be having with this specific model.

 

Aside, the model looks great to me and it's wonderful to know that a 4mm:4mm one exists at Didcot Railway Centre to see in real life too.  Well done Kernow for tackling such an interesting vehicle!

 

[gwrrob]

I've found this old photo of railmotor No.97 somewhere in the west country in 1947.😎

 

[Oldddudders]

13 minutes ago, gwrrob said:

I've found this old photo of railmotor No.97 somewhere in the west country in 1947.😎

 

An amazing find, Robin!

[Gwiwer]

1 hour ago, gwrrob said:

I've found this old photo of railmotor No.97 somewhere in the west country in 1947.😎

 

Cross-post to the realistic modelling thread 

[Deltaskelta]

On 29/01/2024 at 17:45, Deltaskelta said:

No 93 arrived well packed and looking good.  Sadly, a bit stuttery starting off, then after 14 min of forward running at 40% on my Gaugemaster controller,  on the easy curves of my DC layout, it came to a stand with lights still operating.  Applied reverse power and off she went with lights appropriately lit.  Back to forward again and this lime could barely move before stopping with a sound like minced pickups - but nothing visible.  Now the lights have stopped operating too. Can't be bothered lifting the lid so back to Camborne it has gone (actually to  their warehouse at Scorrier).  I didn't mind rearranging the brake gear on the Beattie Well Tanks or filing the front bumper on the Adams Radial but this sounds a bit electronicky to me.  Brian

Update Sat 3rd Feb.  Many thanks, Kernow.  Replacement arrived by return of post and running perfectly, including over the branch line curves and the "crossover from hell".  Brian

[Dana Ashdown]

On 01/02/2024 at 07:51, AY Mod said:

Have you looked at it in the flesh to see how much an issue it is to you personally?

 

I had noticed this before in the earlier product updates from Kernow, but didn't know whether it was an oversight or typical of the actual Railmotors livery. As mine arrived yesterday😃, I can now say that, in some lighting conditions the black does look a bit odd. However, I haven't noticed it all that much, and the model looks pretty perfect otherwise. As to trying to paint the black on the door chocolate, well, unless you can find a true colour match, I would advise leaving it alone.