Sommerfeldt HOm catenary

[Kevin M]

I have a feeling I should have asked a lot more questions before I ordered my overhead wire. I measured and ordered my overhead wire not realizing that the ends are so widely spaced at the masts. Would I be correct to cut out the vertical wire and lowering the support wire to the insulator? Or should I angle the horizontal wire from the mast down so the support wire touches the insulator? I used N scale cork roadbed so the horizontal wire is 71mm above the top of rail when mounted level. The white spacer in the second photo is 67mm high.

 

How do you do it?

 

Another lesson learned: My club wanted my to take my layout to our show last October so I had to do some quick scenery before I had the catenary. I'll never do that again.

 

Thanks,

Kevin

Edited December 11, 2017 by Kevin M

[PaulRhB]

I did drop mine to the sommerfeldt height at first but it's not really right as the lower arm should be near horizontal. On a later section I used longer lengths and cut out their ends and bent the excess length down at one end to make the vertical dropper but left the other end open so I only had one dropper at each joint. It also meant the gap between the wires fitted better. I was lucky in having one of each length to work it out from some secondhand stuff before ordering the rest. Having the lower arm slightly downward does make sure no errant pantograph catches it.

[Kevin M]

Thanks Paul. I didn't have any catenary on hand when I measured out the location of my mast. I assumed that the wire would fit without cutting it. It must be designed for standard gauge. Having to mail order everything makes planning more difficult. It took over two months to get everything I needed. Any way I'll make some adjustments and do as you did.

[Kevin M]

Paul, what mast did you use to mount to the viaduct? And how did you mount it? I have pictures of the prototype but sommerfeldt doesn't seem to offer a bridge mast.

[PaulRhB]

Hi Kevin I cheated

I put them in the trackbed but in the back side with the bridge walkway making them look like they were on the edge.

http://www.rmweb.co.uk/community/uploads/monthly_01_2012/post-6968-0-94263700-1327911305.jpg

The reason was I had to put masts where I couldn't put a deep enough support on the outside so this was the best cheat. Ideally on a less tightly curved bridge I'd have made a plastic or wood representation of the concrete/stone mast base as part of the side and drilled it out and just dropped the mast in.

[Talbotjohn]

HI

I am aware that the type of RhB catenary post (Sommerfeldt #380) shown in this posting has been largely superceded by a different design (Sommerfeldt #389). I have some of both types and was wondering if the two types co-existed in say circa 1981 (period of my layout). I was thinking of having the older type at one end of the layout and in sidings and the more modern type at the other end. The two types would be  separated by lattice gantries spanning the three roads through the station. Any thoughts please?

(Things make a lot more sense now I have the Sommerfedlt instruction book!)