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Improving Dapol GWR signals


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  • RMweb Gold

Dapol’s ready to plant motorised signals with lights were the answer to a prayer for those like me who were daunted by signal kits and their automation.  However, in the looks department they leave something to be desired – or at least the GWR ones do – and can benefit from some cosmetic improvement. 

 

Below is a selection of signals on Stoke Courtenay, which have undergone alteration as follows:

 

1. First of all I temporarily wired them up to make sure they worked before I invalidated the warranty by carving them about.

 

2. I carved off the three raised bands or ledges which go round the post and made good with needle files.  (I think these were probably to help the Chinese assemblers locate the ladder supports and/or provide location for the long-awaited bracket signals.)

 

3. Then the strange ear-like excrescence on the backlight blinder was clipped off and filed smooth.  (Perhaps this too is there to help in factory assembly?).  I used a Xuron track cutter, but learned the hard way not to use a blunt one – I disassembled my first signal that way!

 

4. The arm seems to be neither a 4 foot nor a 5 foot arm but somewhere in between, so I shortened it by 1mm. I made a little jig to do this, scoring the cut then finally cutting through with a razor saw.

 

5. Dummy balance weights were added at foot of post.  I used Alan Gibson parts.

 

6. The safety basket was fabricated from handrail wire (tricky bit of soldering for me) and attached to ladder-top platform with superglue.

 

7. The signal arms (and finial balls) were repainted with Precision signal red. I used self adhesive ‘Solartrim’, a model aircraft product, for the black and white bands on the signal arm. This was cut with a double-bladed knife I made by glueing two Stanley knife blades either side of a strip of Plastikard to give a scale 8” width. I made another simple template for positioning them. 

 

8. The rest of the signal was then repainted.  I used matt white mixed with a good dollop of grey, and Lifecolor dirty back.  I also painted the edges of the signal arm with a dirty black-brown mixture to disguise their thickness.

 

9. Extras such as track circuit diamonds, sighting boards etc. can now be added as desired.

 

10. Final step was to plant the signal, disguise the base with appropriate ground cover, wire up, and hope that it all still worked.  It did.

 

post-15399-0-07314800-1470222292_thumb.jpg

 

post-15399-0-32244500-1470222313_thumb.jpg

 

post-15399-0-68742700-1470222329_thumb.jpg

 

post-15399-0-96088000-1470222348_thumb.jpg

 

 

Not quite the same as a custom-made signal but, I feel, a bit of an improvement while retaining that all-important (for me) “plug ‘n’ play” facility. Now what's happened to those long-awaited bracket signals?  Every year at Warley I'm told, 'Early next year'.

 

​John C.

 

My layout: STOKE COURTENAY, 1930s GWR junction station.  See layout topic.​

 

 

 

 

 

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Hi,

For Brent, bear in mind that it was re-signalled around 1943, so square posts only pre that date.

 

On the question of the Dapol signal, I think that the bits cut off were supposed to represent the guides for the operating rod. Talking of which, I am pretty certain that they never ever operated from the back-blinder.

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  • RMweb Gold

Hi,

For Brent, bear in mind that it was re-signalled around 1943, so square posts only pre that date.

 

On the question of the Dapol signal, I think that the bits cut off were supposed to represent the guides for the operating rod. Talking of which, I am pretty certain that they never ever operated from the back-blinder.

 

Operation via the back blinder is one of the odd peculiarities of the Dapol signal which I can't really understand - especially as it means the down rod finishes up in the wrong place in order to do it that way.

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Hi Checkrail,

 

You have made a nice tidy job of those signals.

In picture three there are still appear to be some bits of mold lines running down the middle of the post?

 

IIRC the signal arms were operated from the cast spectacle plate on the front.

 

Gordon A

Edited by Gordon A
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  • RMweb Gold

The red spectacle should really be elongated. That's why the Dapol GW arm never looked right to me.

 

The spectacle plate is something of a 'let's make it fit' job as far as I can see plus aiming for a bit of robustness - hence it falls between two stools and isn't much good for either.  Not over noticeable in many respects but it will be interesting to see how they've tackled it on the tubular post signals.

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  • RMweb Gold

Thanks all. Some good points here, all of which I was aware of.  On opening my first Dapol signal I was surprised to find the operating wire connected to the backlight blinder.  But of course that was far from being the only bizarre thing about these models.  But we bodgers b***** on in traditional railway modelling fashion trying to improve what the trade gives us according to our skills and time.  I'm very aware that whatever one did to Dapol signals they could never match the exquisite scale models crafted by Stephen and others.  But they serve my purpose.

 

Gordon - yes, the mould line is annoying in the larger-than-life photos but totally invisible in situ on the layout.  I tried and tried to file it away but couldn't get rid of it - it seemed to be almost some stratum within the plastic and I had visions of ending up with a 2mm square post with the seam still there.  So I stopped.

 

Stephen - I'm not convinced that the bits I carved off were meant to represent the down rod guides. They were big projecting ledges round all four sides of the square post.  It'll be interesting to see if the supposedly forthcoming bracket signals use these as locators.  But if you're right it's just another bit of Dapol design eccentricity. Don't want to look a gift horse in the mouth but these signals could have been so much better.

 

John C.

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  • RMweb Gold

 

 

Gordon - yes, the mould line is annoying in the larger-than-life photos but totally invisible in situ on the layout.  I tried and tried to file it away but couldn't get rid of it - it seemed to be almost some stratum within the plastic and I had visions of ending up with a 2mm square post with the seam still there.  So I stopped.

 

 

PS.  I should have realised - of course the seam will go right through.  The post will be made of two parts glued or fused together, with the fibre optic for the light inside.

 

John C.

 

My layout: STOKE COURTENAY, 1930s GWR junction station.  See layout topic.

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Just a note chaps, I've had 4 failures, mine were wired through a Gaugemaster T1 Transformer, (16V AC), as per the instructions, but apparently according to the man at Dapol, they peak at 18V which burns out the Dapol motor.

Dapol phoned me and advised getting a 12V AC Transformer as that would be enough to power the Signal but not enough to damage it.

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  • RMweb Gold

Just a note chaps, I've had 4 failures, mine were wired through a Gaugemaster T1 Transformer, (16V AC), as per the instructions, but apparently according to the man at Dapol, they peak at 18V which burns out the Dapol motor.

Dapol phoned me and advised getting a 12V AC Transformer as that would be enough to power the Signal but not enough to damage it.

That's interesting Andy as I use the accessory part of the Gaugemaster DS and have had no problems.

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there do seem to have been problems with these signals ever since they were released.If the motors are that susceptable then either they need to change them to a higher voltage or modify the design in another way.

For me if they just released a version without the motor I would be tempted, as I don't have depth of baseboard on my ultra light mini layouts.

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Just a note chaps, I've had 4 failures, mine were wired through a Gaugemaster T1 Transformer, (16V AC), as per the instructions, but apparently according to the man at Dapol, they peak at 18V which burns out the Dapol motor.

Dapol phoned me and advised getting a 12V AC Transformer as that would be enough to power the Signal but not enough to damage it.

 

Very interesting, useful and slightly worrying.  I too have used a Gaugemaster 16AC supply.  BUT . . .

 

My understanding of AC voltages is that they quote RMS (Root Mean Square) voltage.  To explain.  If you average an AC voltage then you get 0 Volts as it's positive for half the time and negative for the other half of the time.  So you Square the voltage which gives a positive value and then average (Mean) it.  But that gives you an average voltage that is way too high compared with reality.  So you then take the square Root and quote that voltage as it is relatively meaningful. 

 

Now this results in an RMS voltage that is below peak voltage.  Again, my understanding is that the peak voltage is about 1.4 times the RMS voltage (Square Root of 2 times RMS to be precise).  Being simple minded, I just increase RMS AC voltages by 50% to get a rough idea of peak voltage.  Which wold mean that 12V AC would have a peak around (but slightly under) 18V and 16V AC a peak around 24V.  Note that the same applies to unsmoothed DC.  This is part of the reason why CDUs are so good - they deliver at peak voltage while the capacitor discharges.

 

You will note that my estimate of peak AC voltage is significantly greater than that of the Dapol "expert".  However I believe that it is also true that an off-load transformer will deliver a slightly higher voltage than when on-load - something to do with voltage drop due to resistance?  So the Dapol person may have been comparing off-load (low load) RMS voltage with on-load RMS voltage; not RMS with peak?

Edited by knitpick
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Hi John,

Excellent work on the signals, a big improvement on the out of the box jobs, you mentioned using 'Solartrim' I don't know if you know but there is a product on the market called 'Trimline' by 'Model Technics' it comes in a variety of colours and I think there is about ten different widths of pin stripe on each roll.

 

If anyone is thinking carrying out the same mods as you it might be worth having a look at 'Trimline', it might save the need for the double bladed knife.

 

Michael

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  • 3 years later...
  • 1 year later...
  • RMweb Gold

Digging an old topic up given I’ve just been detailing some Dapol square posts. 
 

 

Would be interested to hear what improvements should be made to the Dapol round post GWR signals, as I also have a pair of those on the bench.

 

also, remembering the issues with motors dying when these were first released.  I know a 9-12v DC supply is now recommended.  Is there any issue with going for a lower voltage supply?  I have a 7.5v supply (150ma)  that I want to use, I am 99% sure that I powered the Dapol signal on Wheal Imogen with a 7.5v supply, but the signal Was hardly used 

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No problem at all using a lower voltage. When I had some Dapol signals, they worked fine off a 5v PSU. The LED was just a bit dimmer, which is no bad thing. 

 

It was mentioned in the long-running Dapol thread that the motor is worked from a 3v(?) regulator. That means that any big more than about 3.5v is just burnt off as heat. My theory is that many of the failed signals are due to burnt out regulators. 

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  • RMweb Gold

Perfect, I couldn’t see any reason a lower voltage should cause problems.  But figures given the history of the product (and the fact they will be pretty inaccessible without causing damage once installed) that it was worth asking.

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  • RMweb Gold

Interestingly in rough testing the 7.5v supply seemed to not be providing enough juice for the motor, to move the signal (the LED on the other hand was a much more pleasing lower brightness.)  Testing with a 9V battery the signals worked find (but the LED was more of a search light).

 

I think I will need to hunt through some more boxes and see if I can find a 9v supply (or heaven forbid go and buy one).  in the mean time I now know each signal works at least so they can all be bolted to the baseboard (and more importantly have the black plastic bases covered with scenics.)

 

 

Edited by The Fatadder
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  • 4 months later...

Here's my attempt at modifying a Dapol, square post, GWR signal.

1. MSE lenses.

2. Backlight. Drilled a hole in the lamp.

3. Modified the blind, so the backlight is visible when the signal is on.

4. Repainted the post.

5. Fitted a dummy operating rod and balance lever.

6. Works off 5v DC. The lamps look more realistic.

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Appearance would be greatly improved if you modified the white band on the arm to more correct proportions. It should be 8" wide, and start 13" from the end of the arm. The same goes for the black band on the back of the arm.

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Bear in mind also that the 'down rod' is intended to push the arm to 'off', not pull it, so the top end attaches to the casting between the pivot and the spectacles, whereas your 'dummy' rod gives the appearance at the top of going to the left of the pivot....

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  • RMweb Gold
35 minutes ago, 4069 said:

Appearance would be greatly improved if you modified the white band on the arm to more correct proportions. It should be 8" wide, and start 13" from the end of the arm. The same goes for the black band on the back of the arm.

In addition the arm on the Dapol square post signals is slightly too long - it needs c.1-2 mm taken off the end of it before repainting the arm and putting the white and black stripes in the right position

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  • 2 weeks later...

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