The last catenary mast (tramway application)

[47137]

My layout will have a short length of overhead line equipment, this is a low voltage system for a tram:

 

The OLE system ends at the left-most mast in this photo, where the track extends as a siding into a works. The system will extend on to the rest of the layout to the right.

 

As far as I can tell, these systems are not tensioned for changes in ambient temperature (well, no pulleys with weights) and the conductor wire is a relatively lightweight item which hangs directly from the masts with a small insulator but no supporting catenary. Please could someone tell me, would there usually be a special kind of mast at the end of the wire? The only examples I can find online are when the wire is taken all the way to the buffer stops, and the final mast is placed in line with the centre of the track.

 

- Richard.

[jim.snowdon]

Normal UK tramway practice is to put the final mast off to one side, essentially to keep it out of the way just in case. The previous mast, which marks the start of the lead out, is sited so as to be beyond the stopping point for the pantograph. Where that isn't practical, alternatives are terminating the wire onto a portal structure, or a bridle slung between two masts either side of the track.

 

Jim

[47137]

Thank you so much!

 

On my layout, the left-most mast in my photo is beyond the stopping point for the pantograph. So this mast can be the last-but-one mast in the system - good

 

Can the final mast be a plain mast (without the cantilevered structure), with an insulator to hold the wire at one side of the track? In other words, making provision to add the cantilever if the wire was ever extended? Or indeed, should the final mast be equipped complete with its cantilever, but with the wire taken across to an insulator on the mast?

 

Sorry to add more questions, but I have a spare Sommerfeldt mast I can use, modified if need be. I think a single (fourth) mast is the simplest way to go, and it would be good to follow UK practice rather than making something up or doing nothing.

 

- Richard.

[jim.snowdon]

The anchor mast would be a plain one with the wire taken straight to it, with an in-line insulator, and a back stay to take the strain from the contact wire tension down to an anchor block. The latter isn't essential, but when the pole is arranged as a cantilever, it needs to be heavier in order to take the strain, with a correspondingly heavier foundation (although that isn't visible on a model).

 

Jim

[47137]

Well ... it seems, the parallel part of a wooden cocktail stick is slightly thinner than the post of a Sommerfeldt mast, and long enough to make an anchor mast if I slip it into a length of brass tubing to make the part nearest the ground. No need to cut up one of my spare Sommerfeldt ones.

 

I imagine the contact wire passing through a scrap of wire insulation to represent the insulator, then through a hole drilled across the cocktail stick near the top and going diagonally down to the ground to represent the back stay / guy wire.

 

I think this will create the right overall effect (this is 1:87 scale), and with the anchor mast in a commercial freight yard I can add a "overhead wires" warning sign to finish it off.

 

- Richard. 

[eastwestdivide]

I've posted pics of the arrangements at Parkgate at the end of the Sheffield-Rotherham tram-train line over here:

http://www.rmweb.co.uk/community/index.php?/topic/56672-tram-trains-for-sheffield-to-rotherham/?p=3035966

 

If you need any more detail, I can go back, as I'm often over there.

Edited February 7, 2018 by eastwestdivide

[47137]

The arrangement at Parkgate with the back stay on the second mast from the end looks useful for many layouts with confined spaces.

 

For my own layout I'll make an anchor post and put the back stay on this because I think this will look best for the location, and I will post up a picture of what I end up with. The anchor post will be round, to match the round section of the Sommerfeldt masts, but a bit more slender.

 

- Richard.

[47137]

I was in Edinburgh last week. At the tram terminus at York Place, the whole catenary assembly (support wire and contact wire) is taken across to a plain pole without a guy wire. Unfortunately I forgot to take a photo.

 

At the airport end of the line, the assembly goes to another plain pole (no guy wire), but this time with a tensioning mechanism:

 

Of all the arrangements I now know, I prefer the style of the arrangement at York Place for my own layout, this seems to be the simplest.

 

- Richard.

[47137]

For the sake of completeness (and me using the RMWeb as a sort of public notebook) here is the mast at the York Place end of the line earlier this month. I will base my model on this one.

 

- Richard.

 

[wagonbasher]

Interesting, the Edinburgh airport buffer stop appears to be a tub of flowers

 

Andy

[47137]

Interesting, the Edinburgh airport buffer stop appears to be a tub of flowers

 

Andy

It's a bit worrying really - I took a third photo which I didn't post above, and really it only confirms the tub of flowers. This was a horrible trip - it was supposed to be an overnight stay for a funeral and I ended up marooned for the rest of the week in the snow.

 

- Richard.