Hi everyone,

I'm working on some higher-level planning for block operation, and came upon a potentially expensive problem: the desire to use contact tracks, but the fact I have about 1000 axles worth of Trix and Roco freight/passenger cars needing conversion to AC wheelsets

I have to do some DCC research to see how the 2 rail guys handle this, but it appears at a glance the account for locomotive draw, and not the cars behind it.

Anyhow, in the spirit of working with what I've got, does anyone have ideas for bridging the existing axles? Two ideas I had are below, but I'm open to suggestions!

1- Find some sort of conductive paint to use from axle shaft to wheel over the insulated bit. This sounds almost too easy, but I don't know an appropriate paint and I worry about reliability

2- Solder the world's shortest wire patch from shaft to inside of the wheel, of course making sure I avoid anything that could interfere with the rails etc... This is assuming the electroplating will accept solder- which I haven't tested yet

Any experience or ideas?

Edited by user 12 January 2023 20:31:37(UTC)  | Reason: factual edit

That would only work with metal bogies. You can buy a conductive ink pen to connect the insulated wheel to the axle. I have used this method. A Google search shpould turn up something you can get locally.

Roger

As they sit, the axles don't work regardless of direction, since they are insulated.

Roger has the right idea with an ink pen, much like my paint idea. Its added to the list. I prefer a paint for removal later if necessary, but ink might come off with a solvent.

I need to check the electrical specs, but I was looking at something like this:

https://www.amazon.com/M...n%2Caps%2C140&sr=8-3

VERY good correction- yes, contact tracks! (with C track) Edit made above

Hello John,
Certainly one possibility for contact would be changing only one axle per car, which would reduce the amount 75% per car with 4 axles and 50% per double axle; you get the idea. Not sure if wheel colour match would be an issue. You could also do both the conductive ink pen and change only one axle to ensure certain contact.

Either way instead of 1000 axles guessing you might be down to 250 to 400 depending on your rolling stock.

- Mark

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That would only work with metal bogies. You can buy a conductive ink pen to connect the insulated wheel to the axle. I have used this method. A Google search shpould turn up something you can get locally.

Roger

Wagons etc are easy because you can just swap the whole axle for AC. You certainly don't need every axle to be AC, really just the end card, end axle (maybe a few in between the end card and loco just for visibility)

What is tricky are some of my Roco AC for Marklin locomotives actually have a DC axle on the front bogie, which means they wouldn't register on the S88 contact until the driving wheels reached it resulting in messed up stopping distances.
For those Roco ones I found the wheels were isolated by a double ended plastic socket. Therefore I drilled out the end of the socket to make a plastic cylinder. I tried filling the gap with conductive liquid but it didn't give contact, the best (and easiest) solution was to buy some tiny cheap metal springs from ebay china, cut them down in length a bit and use those in the middle of the cylinder. Perfect continuity all the time.

Hi John,
I had a thought that may help. Something I have been working out in my drawings and plans.
That is to have 1) magnets and reed switches for one group of locos say Steam, then 2) say circuit track or something slider triggered for diesel and 3) perhaps contact track for electric. This way Rocrail could direct any train from that group to a specific service area or station. JohnJean may tell me that is unnecessary since Rocrail knows where each loco is at any time.

My point is that you may not know which form of feedback for your s88 modules will work best for you until you have your layout planned out and the rolling stock is likely the last thing that you find imperative to bring into its full glory.

Perhaps changing a few cars and building some consists by various methods is best rather than going through all 1000 axles or say 350 cars methodically at once. Why not keep that option as a possibility and just work on how your track should be laid out for the length of trains you desire before diving into that phase of the project?

Step by step.... I am one to talk though, I went all in with a lot of things all at once trying to run before I can walk. I have way too much M-track and now planning on using C for my shadow say. I have a good number of Roco and Piko that fit my era, without a plan to change over my wheels to AC. Signals I have just about the right number (thank you), but have a good number of the old M-track era signals to unload, though I may use a few in less visible areas. ...

I would be curious to hear about your current layout plan in your new digs.
Cheers,
Mark

Well if you are going all in then perhaps your dealer or marklin direct could give you a bulk deal.
In our town we have "Bulk Barn" ...cheaper by the dozen.

Cheers and log in your hours. Let us know how long that takes.

---

Added later: Got curious and boom... Work out a deal for 1000.
https://www.ebay.com/itm/125581461033?

Thanks all! I have a few ideas based on this. I need to get some paint and experiment. It will be a few months, but I will report back on findings!

The resistive paint is made for doing DC S88 detection, which uses current draw to detect the presence of the loco. The paint is like a small resistor that shows up as current draw to the S88 module for that DC variant of S88.
For the 3 conductor AC S88 detection, the electrical connection between the two rails is what is detected.. that is the 'floating isolated' rail when it is grounded to the track ground by the axle , is detected.
If a non-tiny resistance is used rather than a short (which is what the S88 AC detection is looking for), that may well not pull the floating isolated rail down to ground enough.
After all on the DC 2 rail usage, you need to maintain, and not short, the rails as you are connecting the +ve and -ve rails via that resistive paint. (I'm using + and - here for convenience ).

So what I'd try as a solution is a conductive paint that has silver in it for near zero ohm purposes. But as mentioned, the goal really should be to put proper non-insulated wheel sets in, to also get the correct flange dimensions and spacing to run on the tracks in question to get better running over turnouts.

That is an interesting resource in general! Lots of good sizes and more available. thanks for posting!

The length of your contact track is the problem and what the contact does. If the length is so short that the contact is terminated when the un-insulated wheels are off then you might have a problem. You really need to make all the wheels un-insulated. Before buying a bunch of wheelsets I would experiment with the various methods. Should be cheaper.

Jim,
Look up "conductive paint pen" and choose a vendor. I have had success with the MG Chemicals Nickel pen.

Regards,
Roger

Thanks for reviving this thread!

In recent time I have stopped swapping all wheels; When you buy used trains, the dealers free swapping option isnt always possible. So on my my Langer Heinrich (which consists of about 50% TRIX wagons) and my Interzonenzug (which consist mainly of PIKO wagons), I have opted to swap out just 1 or 2 axels on each 4-axeled wagon with AC wheels, thus evenly distribtuting DC and AC wheels all along the train.
Most important thing (for me) is to assure that the final wagon get detected properly, and that there isnt too much time between bridging and non-bridging of the detection track-piece, when the train slowely passes by.

Reminder: When using DC-wheels, it is IMPORTANT to re-gauge the wheels to around 13,8mm for M-track, 13,9mm for K-track and around 14,1mm (actually I dont REALLY know about C ;-)
Failure to re-gauge so WILL cause problems. You should be VERY thorough when re-gauging! I do it expertly with a hammer and a wooden block with a small hole. (Fohrmann would be rolling in his grave...)

Following on from this, has anyone tried the budget "Syringes" of silver paint eBay lists with Chinese origin? I'm left in the comedically ironic situation where I need to bridge an insulated wheel in order to convert FROM three-rail TO two-rail.

I had a look at local sources of conductive paint, but at 80GBP for a single unit - it might be a bit much for painting the backs of four wheels as a once-off!

Otherwise, it's Lima-replacement wheels, pullers and vices!

Cheers!

Everything sold in the USA has a cancer warning attached to it due to the idiotic California legal liabilities - it’s just easier to defacto put the warning on your product rather than comply with requirements to leave it off and risk California legal liabilities.

Car parts shops (motor factors) used to sell bottles of paint to repair heated rear window elements

Something like this:

https://www.ebay.co.uk/i...LRYUcEUXXzRoCUZoQAvD_BwE

or this:

https://www.amazon.co.uk...p;psc=1&gad_source=1

For me, only the leading front axle of the locomotive is of particular importance, as it triggers the enter/in events using contacts.

For this, there are a variety of methods, it depends on the locomotive.

Some locomotives have the same axle as the AC version, but its a double bogie. So you swap the AC axle with the DC - so both locomotives have an AC front and rear DC axle in the bogie.
For example Marklin and Trix BR38's.

Some Roco locomotives have a cylinder that joins the two wheels with a plastic stopper in the middle. You drill out the stopper and then install a small metal spring in the cylinder.

Some Fleischmann locomotives have one wheel with a plastic insert but the other side is metal. So you simply swap one of the wheels between axles of a pair in the double bogie. One becomes conducting (AC) and the other is a 'double' DC (both wheels have plastic insulators)