7mm Electrical feeds to track - above and below board

Dog Star

Western Thunderer
Once you start to make your own track then all sorts of problems challenges come to the fore, for example:- the manufacturer of RTR-track does not make a power connector clip that fits with your choice of rail / sleeper height / ballast method... this thread is to show the way in which I provide an electrical feed to track that I have built. The first photo shows a number of the "droppers" before soldering to the rail... made from brass strip which can be obtained from Eileen's Emporium. Choose a metal section which is the narrower than the width of the rail.

Elec feed pile.jpg

The second photo shows such a dropper soldered to the underside of the rail foot... arranged to be close to the chair and to run down the side of the sleeper.

Elec feed to rail.jpg

If you think that feed looks large...then remember that the sleeper is roughly 6mm wide and 3mm deep... then imagine how much of the metal strip is going to be visible after ballasting.

I use metal strip rather than scrap etch because filing etch to the required width can be a significant consumer of time - for example there are around ten droppers per metre of plain track and maybe a dozen in a typical turnout. The quoted number of droppers reflects model PW where the rails are cut to prototypical lengths, the corresponding numbers for track made with "longest" rail lengths is two for plain line and around five for turnouts.

regards, Graham
 

Dog Star

Western Thunderer
Your count of 10 droppers per metre is a bit eye-watering, though!! Cheapskate that I am, I'd be tempted to take a slight shortcut with your track, and instead of cutting actual scale lengths of rail, see how many scale lengths could be simulated within one actual length (a metre or so?), and just cut the railhead at those points, and cut the metre length to match the end of the scale lengths, if you follow.

Shrewd deductions Detective Jordan. Here is a reasoned response...

The number of ten is because the LNWR was using 30' rails circa 1895 and that means 21cms per (scale) rail length, so five track panels (and ten feeds) per metre of track. The portion of Hartley Hill which is to represent prototype practice of replacing the 30' rails with 60' rails gives just two (and a bit) track panels per metre, hence four feeds and half the work. In passing, for PW diehards, replacing two 30' rails with one 60' rail whilst not replacing the sleepers leads to situations where there are 20 sleepers per 60' rail length rather than the 24 sleepers per length as recorded in LNWR Liveries (HMRS). Study of the photographs in the reference material as noted in the Hartley Hill thread shows that pre-WW1 the number of sleepers per 60' rail could be 20, 21, 22, 23 or 24... (resulting from re-using a sleeper bed with 10 or 11 or 12 or 13 sleepers per 30' rail).

As this time, most of the track which is under construction is associated with the station throat and there is very little plain line track where the length of plain line is greater than 60' (prototype) in length. On other boards there shall be sections of track which approach a metre in length and maybe John and I shall change the method of working for those boards. What is worth noting is that our track plans have rail positions and sleepers according to REA standards for 45' rail lengths... so the sleepers marked on the plan do not correspond with the needs of laying LNWR circa 1900 PW. I made a jig for 30' track panels... I did once make a jig for two 60' panels and the resulting half-sections of track became unwieldy when setting out to the curve of the formation.

regards, Graham
 

Dog Star

Western Thunderer
After laying the track... with droppers for power feed... there comes a time when wire has to be added to the mix so that trains can be run. Up until now the power to the track of Hartley Hill has been provided through the simple expedient of attaching some wire where and when testing has been needed. The time has come when the electrical wiring has to take a more serious turn and hence this post about the next step with the power feeds... provision for attaching wires to the droppers.

Experience with our portable S7 layout and with the layouts of the local club has shown that under-baseboard wiring can get snagged and when that happens the wiring can get pulled off of the track. The droppers which are described in the original post may be difficult to replace neatly if any associated wiring was to get tugged for whatever reason - generally when either moving a layout or working underneath the baseboards - so a method of securing the integrity of the droppers has been developed, that method is described in this post.

This post shows a solder pad to which is attached a dropper and an electrical feed. The pad is made from 0.3mm PCB (other thicknesses are available, actual thickness is not critical - bought from the C&L stand at a show). The dimensions are roughly 1" x 0.5" and that seems suitable for 7mm scale, a smaller size might be desirable for smaller scales. The hole is 2mm diameter and that is large enough for the pad to drop over a track feeder, the hole is offset towards one end of the pad so that a wire can be soldered to the large area of copper.
feeds-pads-one.jpg

This photo shows two track feeds to a plain line piece of track, the holes in the baseboard are 3mm diameter and the strip is 1mm x 0.1mm brass strip from an emporium which attends Telford, Warley, S4um, Wells... no other emporium can compare. The red and black dots are to provide an indication as to how the power is to be connected, being +/- for DC or A/B for DCC.
feeds-plain-1.jpg

A solder pad is coated with epoxy resin on one side and then dropped over a track feed... all of the feeds with a red dot have the "big" piece of the pad pointing to the same side of the baseboard whilst all of the feeds with a black dot have the pad orientated towards the other side of the base board. The dropper is bent over and then soldered to the pad. Not obvious when looking at just two pads, the orientation of the pads provides a visual indication of how to connect the pads to the DC/DCC power bus.
feeds-plain-2.jpg

Crossing vees present a challenge in that the polarity of the vee is dependent upon how the switch blades are set (this feature is a consequence of making track with non-isolating / live crossings). For the feed to a crossing the pad is orientated to be parallel to the baseboard edge... neither one way nor the other!
feeds-vee-1.jpg

and the dropper is soldered as for the feeds to plain track.
feeds-vee-2.jpg

To illustrate how things can get chummy, these are the feeds for switch / closure / stock rails.
feeds-turnout.jpg

regards, Graham
 

Simon

Flying Squad
That's a neat idea, and I like the way the "polarity" of the feed is shown by a simple visual cue.

Simon
 

Dog Star

Western Thunderer
Oh I do like the comedy soldering, it gives me hope for when I get round to building my test track.;):rolleyes:
That is not comedy soldering... that is soldering in the face of adversity! Looks like the Master needs to consider giving the apprentice a lesson in the art of the hot spanner - and no, not the oxy-act in cutting mode.

regards, Graham
 
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