How to do power droppers

[Guest jim s-w]

I thought a little tutorial on how I do droppers might be helpful so here goes (Other dropper based options are available! :tongue )

 

Right then requirements before we start.

 

1 - each rail or rail assembly must have 2 droppers to the power supply

2 - if the solder joint between the rail and the dropper were to fail then the dropper must not be able to fall through the baseboards

3 - the rail must not be secured to droppers at both ends so that its free to slide in the chairs

4 - it has to be quick and simple

 

Stage 1 comes when laying the sleepers as consideration need to be given as to where the droppers are going to be. As I use plastic sleepers I use copperclad for those than need droppers - if you use wood then you can probably stick with wood throughout.

 

The sleeper marked A is not for power droppers but for droppers that hold the stock rail in place. The slide chairs in this area dont actually hold the rail.

 

Each sleeper is drilled and a brass lacemakers pin dropped through. Where there are 4 droppers together this provides an electrical connection between the stock rail and switch rail via the copper clad. Only two of these droppers actually need to be wired to the power supply.

 

The rail with the chairs already threaded on is then glued in place. The droppers are now trapped between the rail and the sleeper.

 

A touch of solder and the job is done! Dont forget to 'gap' the sleepers. A cosmetic chair can be added later. I tend to leave them off the non viewing side so that I can see where the dropper is if I need to know later.

 

As an aside, one compromise I take is to use as long a piece of rail as I can. I really don't like short pieces of rails as I think they are asking for trouble. You can nick the tops and add cosmetic fishplates when its all tested. On a normal point there are only 2 'proper chars between the slide chairs and the rail end. While plastic track is strong I do feel that relying on these 2 chairs to hold the rail on thier own is asking a lot so my solution (purists look away now) it to continue the rail onto normal track bases. I always try to have rail joints in the middle of a 'panel' for ease of alignment.

 

Hope this helps

 

Jim

[The Fatadder]

Looks a very good method! However on my plan I only have a short length which is Bullhead track, so I was wondering what you have used to get power to flat bottom track (or is newstreet all BH?)

[10800]

Useful tips there Jim, thanks!

[craigwelsh]

Jim how easy do you find drilling the sleepers? I've had a go tonight with 0.8mm drills and it seems to take ages to cut through! This is 1.6mm thick stuff from C+L. Looks like fibre rather than the old paxolin.

 

Looks a very good method! However on my plan I only have a short length which is Bullhead track, so I was wondering what you have used to get power to flat bottom track (or is newstreet all BH?)

You could possibly countersink the pin into the sleeper and then flood it in with solder when you solder the rail to the sleeper. I'm not sure if Exactoscale or other FB sleepers allow a tiny amount for the prototype pads?

[The Fatadder]

You could possibly countersink the pin into the sleeper and then flood it in with solder when you solder the rail to the sleeper. I'm not sure if Exactoscale or other FB sleepers allow a tiny amount for the prototype pads?

 

That does sound like a good option, not really going to be suitable for the exactoscale track unfortunately given it would look a bit silly with a wooden sleeper mixed in with the concrete ones, though I guess if it works it could be done at the baseboard joints...

 

Will talk to Colin and see what he recomends for use with his track bits that make up the rest of the track. while they do use an etched spacer between sleeper and rail I'd be a bit unsure about adding further components there for risk of messing with the alignment.

That said, the idea sounds like it would work if you countersunk the pin into the side of the sleeper not under the rail.

[craigwelsh]

That does sound like a good option, not really going to be suitable for the exactoscale track unfortunately given it would look a bit silly with a wooden sleeper mixed in with the concrete ones, though I guess if it works it could be done at the baseboard joints...

 

Will talk to Colin and see what he recomends for use with his track bits that make up the rest of the track. while they do use an etched spacer between sleeper and rail I'd be a bit unsure about adding further components there for risk of messing with the alignment.

That said, the idea sounds like it would work if you countersunk the pin into the side of the sleeper not under the rail.

In my steam centric world I forgot there are depressed centres on those concrete sleepers! If you resin cast a couple of the sleepers you can put a soldering iron near those a lot easier than plastic ones?

 

Following on from my previous post about drilling the copperclad, i've discovered the solution was to buy some better quality drills, armed with some that cut like a knife through Flora it made the job considerably quicker.

 

My first crossing completed using this method, I found larger pins at Hobbycraft (Hemline 0.65mmx20mm 25gm) that had a decent sized head for this purpose and proved a bit better than my original pins. Cheaper alternatives are probably on eBay but these are easy to come by.

 

Now I just need to work on the trickier end!

 

I've put the copperclad sleeper under the nose as when I get around to doing some GWR ones instead this sleeper will feature the slab and bracket chair used by that company. C+L do a lost-wax brass one that Mark Humphries mastered I believe and this will be soldered in place.

 

Thanks again for the technique though Jim.

[Guest jim s-w]

Hi Chaps

 

Sorry I missed your posts. Good to see you sorted out the drill Craig

 

Rich, for FB track there is still a slight gap and you do need to countersink the pin a bit. My method for countersinking is very complex, drill the hole as per the bullhead version and inset the pin. Now comes the tricky bit - next hit the pin with a hammer! The copper is soft enough for the pin head to push itself into and it is all then flush. Paint the sleeper concrete colour and its pretty well hidden.

 

HTH

 

Jim

[59004 ( was Shedcombe....)]

Craig,

 

May I ask why you left the rail sections coming from the crossing roughly a sleeper spacing length short of the actual gap, as can be seen on the drawing underneathh ?

Wouldn't it be more logical, correct and easier to keep the gap where it is designed, and let it function on the model as it would on the prototype ?

The gap can of course be used insulated when done with cosmetic fishplates, so the crossing can be changed in polarity easily still.

 

Otherwise looking good/neat.

 

Regards, Michel

[craigwelsh]

Craig,

 

May I ask why you left the rail sections coming from the crossing roughly a sleeper spacing length short of the actual gap, as can be seen on the drawing underneathh ?

Wouldn't it be more logical, correct and easier to keep the gap where it is designed, and let it function on the model as it would on the prototype ?

The gap can of course be used insulated when done with cosmetic fishplates, so the crossing can be changed in polarity easily still.

 

Otherwise looking good/neat.

Regards, Michel

I suggest you look at some prototype pictures before assuming the template is generally correct, see http://85a.co.uk/forum/view_topic.php?id=646&forum_id=11 , http://ivansphotos.fotopic.net/p55209918.html and http://85a.co.uk/forum/view_topic.php?id=415&forum_id=11 , Martin Wynne mentioned this discrepancy in the Slattocks Junction layout thread on the old forum and i've copied it over to the blog on here.

 

The gap is there as I find it easier to attempt the switch blades as one with the closure rails to lengthen the amount of rail past the flexible blades. I'm not quite an expert enough to do the wing rails and switchblade in one continuous length and then cut through after.

[59004 ( was Shedcombe....)]

Not quite getting what you're on about Craig. All I can see from the pictures you linked to, is that the gap from the crossing rail to the wing rails is there on prototypes where it is on the template, and it's one sleepers spacing distance short on your point.

 

Can enlighten better/differently the explanation of your construction, as I did not get that really.

 

I'm not criticizing you, just wondering and curious, and possibly avoiding an unwanted error.

 

Regards, Michel

[craigwelsh]

Prototype - crossing nose, 2,3,4 break

Mine - as above

Template - 5 sleepers

 

This picture shows the position of the break relative to the nose correctly http://www.templot.com/forum_img/bullhead_crossing_detail2.jpg

 

There is usually a L1 chair or two on the sleeper before the break, Exactoscale have put in another sleeper before the break for strength of plastic construction. Original discussion about this is http://www.rmweb.co.uk/community/index.php/blog/61/entry-191-prototype-track-detail-ramsbottom/

[Guest jim s-w]

My understanding is that it depends on the angle of the crossing. Basically you have to get to full chairs before you can have a break.

 

Cheers

 

Jim

[martin_wynne]

My understanding is that it depends on the angle of the crossing. Basically you have to get to full chairs before you can have a break.

Hi Jim,

 

The length of the wing rail front section is indeed determined by the crossing angle.

 

If you use Templot and leave the default settings, the rail-joint is automatically positioned for you (for REA bullhead and BS-110A inclined FB crossings).

 

Table 14 on p.113 of BRT3 shows the position of the wing rail joints:

 

angle: __________________________ wing rail front spans:

 

up to 1:10 incl. ____________________ 3 timbers

 

over 1:10 and up to 1:15 incl. ______ 4 timbers

 

over 1:15 and up to 1:20 incl. ______ 5 timbers

 

1:21 and over _______________________ 6 timbers

 

regards,

 

Martin.

[martin_wynne]

My first crossing completed using this method

Hi Craig,

 

You have correctly shortened the wing rail front to where it should be, but unfortunately you haven't closed up the timber spacing accordingly. The timber spacing under rail joints is normally reduced from the nominal 30" spacing elsewhere in the crossing. For BH it is either 24" or 25" spacing, for FB it is usually 26" spacing, under joints. (Templot default is 25" -- change as required for your actual prototype.)

 

That's a move of 5" or 6" for the offending timber -- i.e. about half a timber width (12"), so easily noticeable.

 

I have marked up your pic to show what I mean:

 

 

 

 

This is why the Exactoscale templates are so annoying -- the correct positions could easily have been marked with dotted lines.

 

Sorry this is nothing to do with Jim's power droppers -- I never know the correct form when veering off-topic like this. Should I have posted this and my previous post somewhere else?

 

regards,

 

Martin.

[craigwelsh]

edit: Thanks Martin, we cross posted there. I don't think its a problem posting that here as the main focus of the topic was in the first post and I only sought to confirm the application on my point. Its certainly valuable for me to get that corrected and should have taken into account, thanks also for picking up on this thread and confirming i'd got the wing rail length correct. I agree the template is further compromised as a result. Its only the loss of a couple of chairs in any case so i'm glad i've been dithering fitting the closure/switch rails! One thing its a pity Exactoscale don't do is the correct AS1 chair for joint sleepers.

 

Btw I used your method of doing the wing rails and it worked well once i'd worked out the correct sized object to do the tap!

 

 

According to "LMR 95 lbs R.B.S Switches and Crossings (Euston)" wing rails for 1:4 to 1:10 were 12'3 long and for my 1:8 the length to the end of the wing rail form the apparent intersection should be 7'8. I'll have to check if mine matches tonight as I only picked up this document last night. It also gives the chair spacings from which you'd get the timber spanning data Martin provides.

 

My GW pointwork should be somewhat easier I believe as I can just use the equations in David Smith's excellent reference work. Unless you've noted any problems within that Martin?

[Guest jim s-w]

Hi Martin

 

I dunno about everyone else but its all good stuff to me. Do you know if the C&L templates are also wrong? I havent used the exactoscale ones, have I been lucky?

 

Cheers

 

Jim

[martin_wynne]

My GW pointwork should be somewhat easier I believe as I can just use the equations in David Smith's excellent reference work. Unless you've noted any problems within that Martin?

Hi Craig,

 

I have a set of Paddington drawings from the 1940s and 50s and everything that I have cross-checked in the book is correct. I haven't checked everything though. I think you can take it as a reliable source - David Smith obviously knows what he's talking about.

 

Note that if you want to use entirely correct GWR crossings in Templot you will need to create custom templates by doing a bit of timber shoving manually for the uneven spacings. Templot includes the full set of GWR switches pre-defined, but for crossings there are too many variations and the default is for REA only. If you ask on Templot Club, someone may have already done files from the GWR data in the book and be willing to share.

 

regards,

 

Martin.

[craigwelsh]

I have a set of Paddington drawings from the 1940s and 50s and everything that I have cross-checked in the book is correct. I haven't checked everything though. I think you can take it as a reliable source - David Smith obviously knows what he's talking about.

 

Note that if you want to use entirely correct GWR crossings in Templot you will need to create custom templates by doing a bit of timber shoving manually for the uneven spacings. Templot includes the full set of GWR switches pre-defined, but for crossings there are too many variations and the default is for REA only. If you ask on Templot Club, someone may have already done files from the GWR data in the book and be willing to share.

 

regards,

Martin.

Ok that's good to know.

 

Must admit I don't own Templot as I didn't like the interface, i've been doing my own templates from scratch in CAD.

 

The below shows a 1:7 with a B switch and a 12ft loose heel based on the data in David's book:

Someone did print me a 1:7 with loose heel from Templot but your comment on no crossing data may explain why the check rails were an extra sleeper long on the 1:7. Doing them this way takes a little time but i've enjoyed reading how the prototype set these out and the design rules from scratch.

 

GWR timbering is a bit odd anyway as it changed from perpendicular to the centreline of the crossing to perp to the straight road depending on what it butted up against.