Laying Peco 00 Bullhead - soldering, expansion and motorising

[Lacathedrale]

Hi guys,

 

I just wanted to be clear on this before I make any awful mistakes - the peco bullhead unifrog points look like they can have regular metal rail joiners on all rails on all corners, since the frogs are isolated and independently powered by the dropper - is that the case? My plan is to solder droppers to the rear/underside of each rail section since I've only got a dozen or so.

 

I have one 5' baseboard that contains all of my pointwork - would it make sense to solder it up, or should I leave half (or both) sides of a rail join unsoldered?

 

I gather if I'm using servo actuation I should remove the centre-over spring, but is it possible to remove it while the points are in-situ so I can flick with my finger for the time being?

 

Lastly, I'm thinking of using decorators PVA to tack the track down - it's got a long curing time and I'm expecting the ballasting to more firmly grip the track when that happens. Is that a decent approach?

 

Anything else I'm missing?

 

All the best,

[johnb]

On a 5ft board I would strongly suggest that you leave small gaps at rail joints and not solder it up solid for the full length of the board. I'd leave free floating gaps of around 1mm at intervals, as you're using droppers on every length of rail this should not cause problems with current flow through fishplates. Exactly where I can't say as I don't know the track plan, but in my case on a 4ft board with Peco code 100 track, I leave a minimum of a total of 2mm in gaps. My boards are 9mm ply.

 

Remember that you not only have to allow for rail expansion/contraction, but to be aware that the baseboards can move, not much I agree, but enough to cause problems. It's not only temperature, but humidity can cause timber baseboards to expand or contract.

 

I have no knowledge of Peco bullhead rail and components but assuming it is the same metal as Code 100 then it will expand longitudinally the same amount.

 

Fixing down, well ..... you'll get many recommendations on here. I use temporary pins to hold the track in place, then a ballast with watered down PVA to fix, depending on the environment then a 24+ hour setting time is not unusual.

 

Hope that helps

 

John

[Grovenor]

I gather if I'm using servo actuation I should remove the centre-over spring, but is it possible to remove it while the points are in-situ so I can flick with my finger for the time being?

You don't need to remove the spring, servos are easily capable of overcoming the spring. Video shows servo operation of Peco point with spring in place.

https://youtu.be/zcKRknQ2Hew

rgds

[Yardman]

I am building my new layout using Peco Bullhead track as you describe. I do have section breaks as the track will be track circuited. The point frogs are wired through microswitches. Points are servo operated. I do not recommend removing the over centre springs as I have found through experience the servos can have some run back if only powered for a second or so. Especially after operation over a length of time (over 5 years in my case). I suspect the servo gears get run in and reduce gear drag.

I too have glued the track down using PVA without problems. I don't recommend soldering up fishplates, allow for expansion and put bonding wires across fishplates if necessary.

Edited November 23, 2018 by Yardman

[Pete the Elaner]

Hi guys,

 

I just wanted to be clear on this before I make any awful mistakes - the peco bullhead unifrog points look like they can have regular metal rail joiners on all rails on all corners, since the frogs are isolated and independently powered by the dropper - is that the case? My plan is to solder droppers to the rear/underside of each rail section since I've only got a dozen or so.

 

 

Unifrog does indeed work like this. If you are using DCC, this allows you to use conducting rail joiners throughout, but if on DC, make sure you isolate & re-feed after every point.

 allow for expansion and put bonding wires across fishplates if necessary.

P1000996.JPG

I agree with the concept of not trusting rail joiners for conductivity. The joins allow weathering, ballast glue & oxidation to build up. I would not simply use a boding wire across the fishplate though:

I prefer to run a connection from the main feed to each section. At best this allows the current 2 different paths. Although negligible on smaller layouts but on larger ones, the low conductivity of nickel silver rail can become an issue. By using a fresh feed for every piece of rail, you will reduce the chance of issues if you later wire up a larger layout.

But the OP mentioned running a dropper to each rail anyway. Good habit 

Edited November 23, 2018 by Pete the Elaner

[Lacathedrale]

Thank you for the advice on the springs, I just took it for granted but that makes alot of sense.

 

It's not really a problem per-se, but all of my joints are flex to turnout - I want the roads that run onto other baseboards to be fixed at the baseboard edge, so I guess I can solder up the middle section (basically a minories throat stretched out to around 3') and the perimeter tracks, and leave expansion gaps between them all around it, yes?

 

Pete can you please clarify why insulating and re-feeding is required on DC but not DCC? I'm aiming for DCC eventually, but need to wait for my bits to get into stock first so will be operating on DC in the interim.

 

Cheers,

Edited November 23, 2018 by Lacathedrale

[RailWest]

But the OP mentioned running a dropper to each rail anyway. Good habit 

For a belt-and-braces approach you might even want to put two droppers per rail, one near each end. Then if one dropper solder joint fails, and the connection via the fishplates is dodgy, you've still got good power from the other dropper. Probably a bit excessive for scale 60' lengths in 4mm, but might be worthwhile in 7mm and/or in a layout which gets transported a lot (and hence bumped about).

 

Of course, you could even have two parallel power bus feeds, using one for the droppers at one end of a rail and the other for the other end droppers - even more resilience!

 

But maybe life is too short for so much soldering...:-)

Edited November 23, 2018 by RailWest

[Grovenor]

Pete can you please clarify why insulating and re-feeding is required on DC but not DCC? I'm aiming for DCC eventually, but need to wait for my bits to get into stock first so will be operating on DC in the interim.

For DC, if you want to run more than one train you need to divide the layout into sections, insulated joints will be needed for this where self isolating points would do it for you. I thought that unifrog could be used in self isolating mode but if you want to go DCC in future best to keep the sectioning away from the points so it can be easily bypassed in future.

Rgds

[johnb]

 

It's not really a problem per-se, but all of my joints are flex to turnout - I want the roads that run onto other baseboards to be fixed at the baseboard edge, so I guess I can solder up the middle section (basically a minories throat stretched out to around 3') and the perimeter tracks, and leave expansion gaps between them all around it, yes?

 

 

 

Yes there's no issue with soldering up the middle section and allowing the ends of that to float and then fixing the track at baseboard ends. I would leave a 1mm gap in every rail at either side of the middle section.

 

John

[Pete the Elaner]

For DC, if you want to run more than one train you need to divide the layout into sections, insulated joints will be needed for this where self isolating points would do it for you. I thought that unifrog could be used in self isolating mode but if you want to go DCC in future best to keep the sectioning away from the points so it can be easily bypassed in future.

Rgds

Unifrog has no self isolating mode. Only the tip of the frog itself is dead. If you want this live, you must use a switch.

The rails beyond them are fed from the other end of the point, permanently providing power to any sidings. This is great for DCC because you want sidings always powered (although I would always re-feed from a bus anyway) but no so good for DC because you need to turn off power to the sidings.

 

This is different to electrofrog where the rails have their polarity switched.