Thank you. That certainly makes sense. So in either case, the locomotive or streetcar dare not stop at the crossing, lest they stall.
Tramways crossing railways
- Thread starter Steve Manners
- Start date
Gapping is very common on electric trains, particularly with 3rd rail, but it does affect OHLE as well.
There was an emergency engineering possession on the East Coast main line a few years back where over 150M of OHLE was removed, so trains had to take a run up, drop the pantograph, coast through the section and then pop back up on the other side.
From the looks of the photo, the tram has stopped before the dead section, so possibly not related - or maybe it had travelled through and the section was energised at 15KV...
There was an emergency engineering possession on the East Coast main line a few years back where over 150M of OHLE was removed, so trains had to take a run up, drop the pantograph, coast through the section and then pop back up on the other side.
From the looks of the photo, the tram has stopped before the dead section, so possibly not related - or maybe it had travelled through and the section was energised at 15KV...
I did ask in a tramway forum:
Someone wrote:
The crossing is monitored by a DB (German Railway) signal box. When the trains travels, the barriers are closed and the tram's overhead line is switched off. When the barriers are open, the tram always runs on the level crossing with electricity for the tram overhead line. This cable is then connected to the associated "disconnection / connection".
The railroad, on the other hand, always drives over the crossing with momentum, i.e. without electricity. The railroad is allowed to use the crossing much faster than the tram.
Someone wrote:
The crossing is monitored by a DB (German Railway) signal box. When the trains travels, the barriers are closed and the tram's overhead line is switched off. When the barriers are open, the tram always runs on the level crossing with electricity for the tram overhead line. This cable is then connected to the associated "disconnection / connection".
The railroad, on the other hand, always drives over the crossing with momentum, i.e. without electricity. The railroad is allowed to use the crossing much faster than the tram.
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Slightly off-piste, but when the London Overground circuit was completed, there were a few places where it changed from third rail to overhead. Most of them occurred a stations, so nobody noticed, but on the west side, there was one changeover that occurred mid-way between two stations (Shepherds Bush and Willesden Junction) and at one time the trains used to stop to make the change and put the pantograph up. I think this was probably because the train systems needed to shut down and re-boot to the different voltage / current arrangements.
With the newer Bombardier 378 units, they have been able to make the changeover 'on the fly' and passengers do not notice the difference.
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You can actually feel the difference when you ride the train as well. I would describe it as not as smooth - almost gravelly when running on DC. Acceleration is noticeably less as well.
Melbourne still has two remaining tramway/heavy rail crossings. They're both manually controlled by a signal box, which also switches the section of overhead for the crossing between the 1500v heavy rail voltage and 600v tramway voltage.
This is Glenhuntly, where the tramway crosses the three tracks of the Frankston line. As well as suburban trains there is one regular goods train that uses this line every day.
You can see the insulators for the crossing on the tramway side just behind the tram's pantograph, and on the heavy rail to the left. At one point these crossings had mechanical disc signals and catch points for the tramway, but they've since been removed. I don't think the "T" light on the traffic lights is actually interlocked.
The crossing has a 25km/h speed restriction for heavy rail traffic. At one time a type of rail was used here where both the trams and trains ran on the wheel flange to try and reduce noise and wear, but last time it was renewed it was replaced with a more traditional style crossing with a resulting bump as the wheels roll over the flangeways. If you look very carefully just in front of the tram in the lower picture you can see a groove in the concrete, where at some point in the past the tramway catch point has served its intended purpose!
This is Glenhuntly, where the tramway crosses the three tracks of the Frankston line. As well as suburban trains there is one regular goods train that uses this line every day.
You can see the insulators for the crossing on the tramway side just behind the tram's pantograph, and on the heavy rail to the left. At one point these crossings had mechanical disc signals and catch points for the tramway, but they've since been removed. I don't think the "T" light on the traffic lights is actually interlocked.
The crossing has a 25km/h speed restriction for heavy rail traffic. At one time a type of rail was used here where both the trams and trains ran on the wheel flange to try and reduce noise and wear, but last time it was renewed it was replaced with a more traditional style crossing with a resulting bump as the wheels roll over the flangeways. If you look very carefully just in front of the tram in the lower picture you can see a groove in the concrete, where at some point in the past the tramway catch point has served its intended purpose!
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In Lisbon, Portugal, there is a grade crossing between the Iberian Gauge (5' 6" - 1,668mm) line connecting the otherwise isolated Cascais railway with the rest of the network, and the 900mm tram system. The Lisbon trams were traditional, wooden-bodied cars with conventional steel spoked wheels and relatively primitive suspension, (as opposed to today's technology with rubber springing and resilient wheels) until the 1990s. I went there with a tape recorder to capture the sound of these old cars rattling across the gaps in the track.
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The late lamented Chicago North Shore and Milwaukie interurban used to use the 3rd rail tracks of the Chicago 'El' to serve downtown Chicago, it then ran on overhead on its own right of way for the rest of the journey. The change from 3rd rail to ole was done on the fly USING TROLLEY POLES the Conductor of the interurban used the trolley rope to 'fish in the air' to catch the wire - something of a skilled job!
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That sounds like fun. I suspect on occasion the wire wouldn't just be caught but reeled in as well!
What is also impressive is that they could run at over 90mph, using trolley poles on tramway-type ole. You will also note that they did this with two poles in contact with the wire, something that modern railway men will tell you is impossible...
