How do overhead power lines crossover?

[FraserW08]

Looking for a bit of help with my uni project. How does the OLE crossover onto another rail line? Using the third rail you need gaps if you have a junction but from my observations at Glasgow Central the lines all cross over, giving seamless power to the train? Sorry if I've maybe said something wrong, trying to get a better understanding of the OLE.

Thanks Fraser

 

[Domh245]

This document by Gary Keemor should answer your question

 

[FraserW08]

This document by Gary Keemor should answer your question

Thanks will have a read through, looks promising an could help with more areas of my project.

 

[30907]

Not surprised you can't fathom the knitting at a complex station like Central. You could seek out a smaller one with a crossover or suchlike which you can see from the platform, and see what you make of that. Sorry I don't know the area well enough to be specific.

 

[FraserW08]

Not surprised you can't fathom the knitting at a complex station like Central. You could seek out a smaller one with a crossover or suchlike which you can see from the platform, and see what you make of that. Sorry I don't know the area well enough to be specific.

No bother, might be going out on a site visit to Babcock Rail to support my project, just need to get some information for a report and when travelling into town i notice the wires at Glasgow Central are everywhere.

 

[TT-ONR-NRN]

No bother, might be going out on a site visit to Babcock Rail to support my project, just need to get some information for a report and when travelling into town i notice the wires at Glasgow Central are everywhere.

Ooh, I’m going to Glasgow Central in January with Virgin, I will look our for the weird electrification!!!

 

[Domh245]

I will look our for the weird electrification!!!

It's not that it's weird, it's just complicated. Any other station with a complicated track layout (Manchester Piccadilly, Euston, Liverpool Street, etc) will have a complex arrangement to make the overhead wiring work

 

[TT-ONR-NRN]

It's not that it's weird, it's just complicated. Any other station with a complicated track layout (Manchester Piccadilly, Euston, Liverpool Street, etc) will have a complex arrangement to make the overhead wiring work

Oh I see.

I noticed on some complex trolleybus and tram networks abroad they use a sort of ring on the overhead wires, does that happen with railways?

 

[driver_m]

You usually get a couple of wire runs which are separated from each other. However if you look at the one at Colwich Jn on the diamond crossover, the wire is joined together. I often seem to get a bit of pan bounce here and lose the overheads momentarily.

 

[Domh245]

Oh I see.

I noticed on some complex trolleybus and tram networks abroad they use a sort of ring on the overhead wires, does that happen with railways?

Without knowing what it is you are talking about exactly, it's unlikely. Trolleybus systems tend to be very complex in comparison to rail systems as they need to have 2 contact wires (live and return) instead of the one that the railway can have, so you have to have put in insulating sections with wires looping around above that to keep the electrical feeding, like this. Rail ones can be simpler as the whole thing is at 25kV, so you don't need to start putting insulators and the rest of it in.

 

[edwin_m]

I think that's actually a crossing of a trolleybus with a tram overhead designed for trams with pantographs. Look closely at the one going top left to bottom right and it is actually a contact wire (with gaps for the trolleys to pass through) below a supporting catenary wire, not two wires level with each other. I've seen some in Riga (sorry no photos) which were somewhat simpler than that one.

 

[daikilo]

To provide a simple answer to the original question, heavy rail OHLE does not "need" to cross-over as it is only supplying a power source and has nothing to do with train control. The train only needs power from somewhere so it can slide from one power-line to another. What somplicates matters is when the number of tracks and overhead lines reduces and when individual lines reach a certain length; in both cases said lines will have a tensioner on at least one end. Indeed maintaining adequate tension is probably a more significant issue on open higher-speed track than arrainging the knitting outside a station. Note that it is quite normal to have the pantograph yemporarily picking up from two power lines above poitwork.

The same basic logic occurs with a conductor rail, but in that case there needs to be breaks because of the phyical contacts that would otherwise be made.

 

[DarloRich]

Ooh, I’m going to Glasgow Central in January with Virgin, I will look our for the weird electrification!!!

it isnt in any way weird. It is normal for a large station.

 

[racyrich]

I remember being in Salzburg and cycling over a level crossing of an electrified line with a trolleybus route. Even after staring at the maze above me I couldn't figure out how it worked.

 

[zuriblue]

In Aarau, Switzerland there are 2 points where the Wynental und Suhrentalbahn (narrow gauge interurban electrified at 750VDC) has a junction with the Lenzburg-Zofingen line of the SBB (15 kV, 16.7 Hz). Both sets of stock have pantographs so I suspect that there is a neutral section. In Zürich they were proposing extending one of the trolleybus routes to Affoltern, again crossing an SBB line energised at 15kV but in the end they didn't get permission.

 

[Mag_seven]

I remember being in Salzburg and cycling over a level crossing of an electrified line with a trolleybus route. Even after staring at the maze above me I couldn't figure out how it worked.

Like this:

https://www.railscot.co.uk/img/49/880/

 

[swt_passenger]

Getting back to crossovers between running lines on the mainline railway, I think a useful way of finding out how it is done is to run a cab view video in slow motion. The run out of Euston here

shows a few differnt examples through the station throat area, but basically the catenary doesn't ever actually cross over at the same height as the pantograph runs, the line going off through a set of points is basically brought down from above to the same level as the main route before the points, and then moves away while being held at the same level.