Fitting Resistors to Axles

[St. Simon]

Hi,

 

A big job that is staring me in the face for the new layout is fitting the axles of all my stock with resistors to

activate my track circuits.

 

I’ve watched a couple of videos that use surface mount resistors and conductive paint. However, it just looks very fiddly to do on 100+ axles.

 

So, what other methods are there?

 

Simon

[Dagworth]

Paint the axles with this, takes seconds, I can do many wagons in an evening when I get round to it

 

https://www.dcctrainautomation.co.uk/uhlenbrock-40410-resistive-paint-10-ml.html

 

Andi

[WIMorrison]

Just do the rear most axle of the last wagon

[Dagworth]

1 minute ago, WIMorrison said:

Just do the rear most axle of the last wagon

I have found that in some circumstances that can allow points to change under the middle of the train 

 

Andi

[WIMorrison]

You need to change the software that you are using as decent software will not change any turnouts in the situation where the from of a train has lost some of the rear.

Edited October 20, 2021 by WIMorrison
Spelling

[peach james]

I do about 1/6 of the wagons, brake vans, BCK's, BSK's & BG's.  That should ensure enough detection to avoid the problem mentioned ^, of trains lacking detection having the turnouts change under them.  It also should allow the control software to stop the train if the train separates - but as I'm running a rather obsolete version of RR&Co (5.7), it doesn't allow for an easy way to do so.

If you can get the resistive ink pen, it is easier than soldering to the backs of wheels

[jamespetts]

1 hour ago, Dagworth said:

Paint the axles with this, takes seconds, I can do many wagons in an evening when I get round to it

 

https://www.dcctrainautomation.co.uk/uhlenbrock-40410-resistive-paint-10-ml.html

 

Andi

 

I have tried resistive paint in the past on N gauge axles, but found that it was not reliable: as the paint dried, I think, it would crack and form breaks in the conductivity.

 

I wonder whether the particular type of resistive paint makes a difference?

[Dagworth]

I have used the Uhlenbrock paint linked to above on hundreds of axles and not noticed any issues at all. Then again though with at train of 70 to 100 axles would I see a problem if some axles went open circuit?

 

The amount of time it takes to paint axles is so small it may be worth a second coat if needed.

 

Andi

[Michael Hodgson]

1 hour ago, Dagworth said:

Paint the axles with this, takes seconds, I can do many wagons in an evening when I get round to it

 

https://www.dcctrainautomation.co.uk/uhlenbrock-40410-resistive-paint-10-ml.html

 

Andi

It's a job I need to do but haven't tried yet.  I haven't decided whether to solder SMD resistors on, or to take your easier option.  I have been told however that the stuff is unreliable in that it wears off over time.  Do you find that a problem ?

 

Do you find that you can get a reasonably consistent resistance as between different axles, as it depends on the thickness of the coating.  I am told you can adjust the resistance by adding a second coat if the resistance is too high and burnishing some off if it's too low.  

 

I am told that 10k is enough to operate most detectors, but nearer 1k for Railcom.

Also been told that if the wheel are chemically blackened you need to remove that from the back of the wheels with a wire brush.

[Michael Hodgson]

45 minutes ago, peach james said:

I do about 1/6 of the wagons, brake vans, BCK's, BSK's & BG's.  That should ensure enough detection to avoid the problem mentioned ^, of trains lacking detection having the turnouts change under them.  

 

That sounds to me like a sensible compromise to make.  Do you do every axle on the vehicles you do or just one?  My feeling is the latter is potentially unreliable, like having only one axle pickup on a loco.

[peach james]

Only one on goods stock and inner coaches, because they should not be the only thing detected, but two on brake vans/brakes.  That seems the most sensible compromise.  (& more specifically, 2 on the rear BCK or BSK, because they are only run in directional sets by choice)

I also set ~5 seconds delay on clear for occupancy, which helps with minimizing the risk of "flickering" over the occupancy to a following train & resulting in a rear end accident.  Why?  Because to error is human, to really make a mistake usually adds a computer program

James

[St. Simon]

10 hours ago, WIMorrison said:

You need to change the software that you are using as decent software will not change any turnouts in the situation where the from of a train has lost some of the rear.

 

Hi,

 

My software is written to act like an actual interlocking which will allow the release of a route if a track circuit goes clear on the approach to point.

 

So I'm going to have to fit resistors to all axles on a 4-wheel vehicle and one axle on each bogie of a 8-wheeled vehicle.

 

Simon

[Philou]

I ask the question as I'm curious - Why? Why are the axles being painted/resistors? Are the systems that you are using for DCC? (I'm going DCC only).

 

If all of this has already been explored in detail, to save you repeating, just point me in the right direction. Thanks.

 

Cheers,

 

Philip

[Dagworth]

24 minutes ago, Philou said:

I ask the question as I'm curious - Why? Why are the axles being painted/resistors? Are the systems that you are using for DCC? (I'm going DCC only).

 

If all of this has already been explored in detail, to save you repeating, just point me in the right direction. Thanks.

 

Cheers,

 

Philip

Because in order for the whole train and not just the loco to be detected all (or many more than just the loco) wheels need to draw some current from the rails. This only needs to be milliamps so an axle with a resistance of about 10k is enough. My detection is sensitive enough that for testing I can use a damp finger across the rails to trigger a circuit. 
Detection does work best in DCC where there is constant power to the rails, it can be done with DC by imposing a high frequency signal across the rails that will not drive a motor but it’s a lot less easy. 
 

Last summer I extended the track circuits on Ravens to include the fiddle yards as well, plan being to automate trains moving up when the road in front becomes vacant. 
 

Andi 

Edited October 21, 2021 by Dagworth

[St. Simon]

Hi,

 

I’ve now started to fit wheels with resistors, using small standard resistors and conductive paint and it seems to work other than two small problems.

 

Dirty Track and Dirty Wheels. So the question now is, how do you guys keep the wheels on unpowered stock clean?

 

Simon

[WIMorrison]

I use a round brass brush in my Dremel which I have rotating at a slow(ish) speed. I turn the wagon/coach upside down into a foam cradle and lay the Dremel on one wheel and place a finger very lightly on the other wheel to create a tiny bit of drag. This then cleans the wheel of the hard built-up crud.

 

Sometimes I will repeat this process, again with the Dremel on one wheel but on the other I use a cotton bud dipped in white spirit on the other to 'polish up' the wheel afterwards.

[DCB]

16 minutes ago, St. Simon said:

Dirty Track and Dirty Wheels. So the question now is, how do you guys keep the wheels on unpowered stock clean?

 

Simon

You can't.   What is required is a pair pf revolving brushes which bear against the wheel treads which revolve in the same direction at different speeds.   If one brush revolves against one wheel and the other against the other wheel, or a finger or file rubs the other wheel then wheels can come loose, especially the narrow  Jackson etc type.   I had goodish results with brass strips rubbing the treads to provide pick up for my illuminated brake van but it does equal mileage forwards and backwards, if travelling one way crud rapidly builds up.   Relcos help with powered wheels,  I have several Hornby Dublo bogies with Lima wheels which pick up through pin point bearings under various coaches. These are very free running but they do very little running so as to keep the wheels clean for showing off when visitors come.  My automated signalling used magnets under the last brakevan on the train and proved too expensive to install , t was mighty weird and could not cope with being switched off with trains out on the layout rather than stopped at signals.   Probably the same fault lurks within other systems

[WIMorrison]

2 minutes ago, DCB said:

You can't.   What is required is a pair pf revolving brushes which bear against the wheel treads which revolve in the same direction at different speeds.   If one brush revolves against one wheel and the other against the other wheel, or a finger or file rubs the other wheel then wheels can come loose, especially the narrow  Jackson etc type. 

 

Rubbish, I have described the method I have used for many years and haven't seen the issue you describe on a single wheel - though I grant it could potentially happen if you are very heavy-handed, but if you are then you wouldn't be using the method I describe.

 

Plus two brushes rotating at different speeds is doing exactly the same as I have described, ergo you have destroyed your own argument.

 

3 minutes ago, DCB said:

 Relcos help with powered wheels, 

 

DO NOT USE Relco units anywhere near your DCC layout as you will destroy all your decoders very quickly.

 

[DCB]

2 minutes ago, WIMorrison said:

 

Rubbish, I have described the method I have used for many years and haven't seen the issue you describe on a single wheel - though I grant it could potentially happen if you are very heavy-handed, but if you are then you wouldn't be using the method I describe.

 

Plus two brushes rotating at different speeds is doing exactly the same as I have described, ergo you have destroyed your own argument.

 

 

DO NOT USE Relco units anywhere near your DCC layout as you will destroy all your decoders very quickly.

 

You mis understand, two brushes on the same wheel tread. that way the wheel revolves but at least one brush is moving at a different speed to the wheel, without twisting the wheel on the axle, or stalling the wheel and putting a flat on the tyre.  like my knurled wheel track cleaner/ grinder, its got one 2 start and one single start worm so one axle revolves twice as fast as the other.   Most of the gunge is caused by arcing and burning of the rails, changing from track power cures it,  I know this because I went from track power to battery power n my garden layout.  The new gunge is completely different much less rubbery and the wheels look like they have been sand blasted and coated with limescale, and derailments become more frequent unless the gauge corners of curves are kept clean.

[JimFin]

A method I use may help with the wheel cleaning, although I have no experience of detection.

 

I have a narrow strip (about 1cm) of blue paper towel held across the track at the entrance/exit to the fiddle yard. There are screws fixed to each side of the track and the strip held in place with magnets.

 

The strip is kept damp with a few drops of cleaning alcohol which picks up dirt from all the wheels passing over it. As it becomes dirty, just swap. Means all wheels get a clean whenever they pass over it.

 

 

[N Quay Harbour]

On 20/06/2022 at 23:41, St. Simon said:

I’ve now started to fit wheels with resistors, using small standard resistors and conductive paint and it seems to work ....

Can you or anyone else tell me what size 10k smd resistors I should use for N gauge... and a possible supplier? I read somewhere that someone was using 0602 but I can only find 0603 specs, so can't compare.

[WIMorrison]

I’m not sure that there is an 0602 which would be 1.5mm x 0.5mm (60thou x 20thou).

I use 0603 and they are pretty small and not easy to glue on axles and then get the paint onto.

[Tim123]

£0.484 for a pack of 100 excluding VAT and postage from Rapid Electronics. As Iain said 0603 sized. 

 

https://www.rapidonline.com/10k-0603-1-1-10w-royal-ohm-chip-resistor-pack-of-100-72-9849

 

I've used Rapid Electronics for years, both for work and personal use. Never had any issues, and they live up to their name!