Editing Overhead line (section)

== Crossings ==
[[File:Tramtrol 029148ed.jpg|thumb|Tram overhead wire (diagonal) crossing trolleybus wires (horizontal), photographed in Bahnhofplatz, Bern, Switzerland]]
[[File:Tramtrol 029148an.jpg|thumb|right|Annotated version of the previous photo, highlighting components
{{legend|#0C21EE|tram conductor}}
{{legend|#089B0C|trolley bus wires}}
{{legend|#CAFF06|insulated trough}}]]

[[Tram]]s draw their power from a single overhead wire at about 500 to 750&nbsp;[[volts|V]] DC. [[Trolleybus]]es draw from two overhead wires at a similar voltage, and at least one of the trolleybus wires must be insulated from tram wires. This is usually done by the trolleybus wires running continuously through the crossing, with the tram [[electrical conductor|conductors]] a few centimetres lower. Close to the junction on each side, the tram wire turns into a solid bar running parallel to the trolleybus wires for about half a metre. Another bar similarly angled at its ends is hung between the trolleybus wires, electrically connected above to the tram wire. The tram's pantograph bridges the gap between the different conductors, providing it with a continuous pickup.

Where the tram wire crosses, the trolleybus wires are protected by an inverted trough of [[Electrical insulation|insulating]] material extending {{convert|20|or|30|mm|abbr=on}} below.

Until 1946, a level crossing in [[Stockholm]], [[Sweden]] connected the [[railway]] south of Stockholm Central Station and a tramway. The tramway operated on 600–700&nbsp;V DC and the railway on [[15 kV AC railway electrification|15 kV AC]]. In the Swiss village of [[Oberentfelden]], the [[Menziken–Aarau–Schöftland railway line|Menziken–Aarau–Schöftland line]] operating at 750&nbsp;V DC crosses the [[Swiss Federal Railways|SBB]] line at 15&nbsp;kV AC; there used to be a similar crossing between the two lines at [[Suhr, Aargau|Suhr]] but this was replaced by an underpass in 2010. Some crossings between tramway/light rail and railways are extant in Germany. In [[Zürich]], Switzerland, [[Verkehrsbetriebe Zürich|VBZ]] [[trolleybus]] line 32 has a level crossing with the 1,200&nbsp;V [[Direct current|DC]] [[Uetliberg railway line]]; at many places, trolleybus lines cross the tramway. In some cities, trolleybuses and trams shared a positive (feed) wire. In such cases, a normal trolleybus frog can be used.

Alternatively, section breaks can be sited at the crossing point, so that the crossing is electrically dead.

=== Australia ===
Many cities had trams and trolleybuses using trolley poles. They used insulated crossovers, which required tram drivers to put the controller into neutral and coast through. Trolleybus drivers had to either lift off the accelerator or switch to auxiliary power.

In [[Melbourne]], Victoria, tram drivers put the controller into neutral and coast through section insulators, indicated by insulator markings between the rails.

Melbourne has several remaining [[level crossing]]s between electrified suburban railways and tram lines. They have mechanical switching arrangements (changeover switch) to switch the 1500 V DC overhead of the railway and the 650 V DC of the trams, called a Tram Square.<ref>[https://web.archive.org/web/20071208021201/http://www.tmsv.org.au/papers/lvlcross.htm TMSV: Tramway level crossings in Victoria]</ref> Several such crossings have been grade separated in recent years as part of the [[Level Crossing Removal Project]].

=== Greece ===
[[Athens]] has two crossings of [[Athens Tram|tram]] and trolleybus wires, at Vas. Amalias Avenue and Vas. Olgas Avenue, and at Ardittou Street and Athanasiou Diakou Street. They use the above-mentioned solution.

=== Italy ===
In [[Rome]], at the crossing between Viale Regina Margherita and Via Nomentana, tram and trolleybus lines cross: tram on Viale Regina Margherita and trolleybus on Via Nomentana. The crossing is orthogonal, therefore the typical arrangement was not available.

In [[Milan]], most [[Trams in Milan|tram lines]] cross [[Trolleybuses in Milan|its circular trolleybus line]] once or twice. Trolleybus and tram wires run parallel in streets such as viale Stelvio, viale Umbria and viale Tibaldi.