Talk:Trolleybuses in St. Gallen

What does this mean?

The article contains the sentence:

At that station, both systems use a common overhead wire about 300 m (980 ft) in length, but are electrically isolated from each other.

I think this needs clarification. It isn't obvious how two systems can share the same overhead wire but be electrically isolated from each other. If this really means a 'common overhead wire' then the only possibility I can thing of is some sort of time based system, where the wire is energised at one voltage at certain times, and at another at other times. I know this is done occasionally where two electric railways meet, but it would seem odd to do it between a railway and a trolleybus line. Alternatively, I wonder if it really means that there multiple wires at different voltages sharing a common support structure. I can see that this is a translation from the German WP article, but (at least to my level of German) that seems equally unclear. Can somebody clarify?. -- chris_j_wood (talk) 09:29, 9 July 2014 (UTC)

I've managed to locate the place on Google Maps (here) but I'm now even more confused. The railway appears to be on its own road-side right of way, albeit with a level crossing that is nowhere near 300m long and which the trolleybus doesn't seem to cross. My best guess is that the two systems simply share the same suspension structure and not the actual wire. If that is the case, I don't see that as being sufficiently notable to be worthy of inclusion in the article. I'll leave the {{clarify}} for a while to see if I'm contradicted; if not I shall remove the reference. -- chris_j_wood (talk) 09:55, 9 July 2014 (UTC)

It appears to refer to span wires, not contact wire, in which case it is not worth noting. That text came from the German version of the article, when translated in January 2012 by Bahnfrend. The German version refers to "gemeinsame Fahrdrahtaufhängung", which my large German-English dictionary says means "common overhead-contract-wire suspension", with Aufhängung meaning suspension. This was probably too uncommon a term for online translation software to handle. I think you can delete it. SJ Morg (talk) 10:07, 9 July 2014 (UTC)

Yes, it was my faulty translation. Thanks for the headsup. I've now corrected the error, and substituted a better infobox image. (I can't remember whether I used online translation for "Fahrdrahtaufhängung", but google presently translates it as "catenary suspension".) There's a picture of the catenary arrangement here. Although the arrangement is not notable enough for its own article, I think it's interesting and encyclopedic enough to be included in an article about the system as a whole. By coincidence, I'm about to visit Switzerland for the first time in five years, and after I return home, I will update all the articles about Swiss trolleybus systems. Bahnfrend (talk) 20:05, 9 July 2014 (UTC)

Thanks, Bahnfrend. Although I'm not convinced the shared traction poles and spans wires are worthy of note – what other arrangement could there be for trams and trolleybuses running in mixed traffic along the same section of street? – I don't care much one way or the other. SJ Morg (talk) 06:42, 10 July 2014 (UTC)

Likewise, thanks Bahnfrend. Although the picture you link relates to the common section between the Trogenerbahn and the trolleybus (which is not electrically isolated; both operate off the same supply if not the same wire) rather than the section under discussion. I agree with SJ Morg on the notability of the latter (not totally convinced but not a big issue). -- chris_j_wood (talk) 10:36, 10 July 2014 (UTC)