Unusual PW configurations thread both real and model.

[ejstubbs]

Spotted this during a wander round Manchester yesterday:

 

 

It's where Windmill Street crosses the tram tracks coming down off the bridge over Great Bridgwater Street, outside the front of the ex-Manchester Central Station, now a convention centre.

 

It's basically an oddly stretched turnout, with the switch rails on one side of the road crossing, the two routes then running in a sort of gauntlet arrangement through the road crossing before finally separating on the other side.  Anyone know why it was built like this?  I thought maybe it was to keep the switch moving switch rails away from the road crossing (and I think the pedestrian crossing beyond it).  Would that make sense?

[eastwestdivide]

Is the chequerplate in the foreground in a tram-only part of the road? If so, maintenance would be easier, not having to close the trafficked road that crosses over. Also avoids heavy vehicle impacts to the cover and the ends of the switch rails.

[martin_wynne]

Similar arrangements occur on railways too, in order to put the switch in a more convenient place. Sometimes the gauntletted section can be very long. For example in mechanical signalling to keep the switch within the 350-yard rodding limit from the signal box, when the actual junction is much further away. Or if the tracks cross a swing bridge you obviously don't want the rodding to cross the bridge to a switch on the far side.

 

Martin.

[ejstubbs]

Is the chequerplate in the foreground in a tram-only part of the road? If so, maintenance would be easier, not having to close the trafficked road that crosses over. Also avoids heavy vehicle impacts to the cover and the ends of the switch rails.

 

Yes it is.  All the concrete surfaces are tram-only.  That said, there appears to be sufficient space on the other side of the road crossing for the switch rails and their subterranean operating mechanism.  I suspect it's the presence of the pedestrian crossing just beyond the road crossing that rules out a more conventional turnout configuration.  By pedestrian crossing I don't mean a zebra crossing or a signal controlled crossing: IIRC it was just dropped kerbs and tactile paving.  (I admit that my memory of the layout should be rather better because of course I crossed the tram tracks using the facilities provided and of course I didn't stand in the middle of the tram track to take the photo, what could possibly make you think that, officer?  Which sparks another question: which force has jurisdiction on the trams - is it Greater Manchester Police or the BTP?)

 

The whole setup seems relatively new.  Google Streetview's photos from April 2016 show it still in the process of construction/commissioning, and there's no turnout visible on the Google Maps satellite view.

[eastwestdivide]

Back in the mountains, I came across this passing loop on the funicular up to the Reichenbach Falls, Meiringen, Switzerland.

 

A bit of research and I discovered that it's known in German as an Abtsche Weiche (roughly "Abt's points"), after the engineer Carl Roman Abt, famous for rack railways. It relies on the "inner" wheels of each car being relatively wide, and having no flanges, and the "outer" wheels having two flanges. Pictures to explain it at the German wikipedia page (no English equivalent that I could find).

The wheels are guide wheels for the wire ropes, so you can tell that I'm looking downhill because no ropes are visible.

Edited September 28, 2016 by eastwestdivide

[jim.snowdon]

What you came across in Manchester is not uncommon in tramways and can be decided by several factors. In this case, the obvious one is that should the tram driver have to manually operate the points, he can do so without having to stop the tram across the road. It can also be found, in mainland Europe, where the tram stop is immediately before a junction, as it lets a following tram set the points automatically whilst the first tram is still at the stop. It is effectively barred in the UK by the Disability Discrimination Act, as the offset makes it impossible to meet the statutory requirements for the tram/platform gap. (European legislation for the disabled, actually Persons with Reduced Mobility, is more practical than its UK embodiment.)

Alternatively, such an arrangement can be used simply to get the points out of the carriageway, especially where there is turning traffic.

 

Jim

[Re6/6]

This would make an interesting build!

 

Photo: Henry Priestley/Colin Garratt./The Golden Years of British Trams/National Tramway Museum.

 

 

[jim.snowdon]

And on the Croydon Tramlink system, at Mitcham, where earlier buttressing to a failing retaining wall precluded normal double track, and interlacing saved two sets of switches and mechanisms.

 

However, the piece de resistance of track interlacing probably has to be this specimen, which was installed on Stuttgart tramway system in 1997. Not only is it a crossover within the interlace, but because Stuttgart were installing dual gauge track as part oftheir phased changeover from metre to standard gauge, it is interlaced dual gauge as well. The crossover is still there, albeit now standard gauge only as the changeover from metre gauge has been completed. There are, to judge by the cab videos on youtube, still quite a few dual gauge junctions still in place on the street sections of the system simply because it is impractical to remove the metre gauge rails other than when the whole junction comes up for renewal.

 

 

 

Both pictures appeared in the June 1997 issue of what was then Light Rail & Modern Tramway magazine.

 

Jim

[phil-b259]

Yes it is.  All the concrete surfaces are tram-only.  That said, there appears to be sufficient space on the other side of the road crossing for the switch rails and their subterranean operating mechanism.  I suspect it's the presence of the pedestrian crossing just beyond the road crossing that rules out a more conventional turnout configuration.  By pedestrian crossing I don't mean a zebra crossing or a signal controlled crossing: IIRC it was just dropped kerbs and tactile paving.  (I admit that my memory of the layout should be rather better because of course I crossed the tram tracks using the facilities provided and of course I didn't stand in the middle of the tram track to take the photo, what could possibly make you think that, officer?  Which sparks another question: which force has jurisdiction on the trams - is it Greater Manchester Police or the BTP?)

 

The whole setup seems relatively new.  Google Streetview's photos from April 2016 show it still in the process of construction/commissioning, and there's no turnout visible on the Google Maps satellite view.

 

I believe it depends to some extent on the location of the tramway.

 

The first thing to remember is that on sections shared with pedestrians or other motorised vehicles (or where they run alongside the same with no fencing securing the tram tracks from trespassers), trams are treated by law as if they were Buses. Thus trams are fitted with indicators and brake lights as per cars, and if an accident were to occur then it would be processed using motoring driving offences. Such sections do not usually have signalling as such - while their are tram signals associated with facing points and traffic lights, the onus is on the driver of the tram to ensure they can stop in the distance they can see to be clear. It therefore follows that Policing for on road sections is the responsibility of the territorial force concerned - in Manchester's case GMP

 

On segregated fenced in alignments, were the public are trespassing if they go onto the track, then railway rules apply allowing higher speeds combined with a propper signalling system and while this in theory makes the BTP the relevant authority, in practice many operators will probably continue to make arrangements with the local police force instead. This mirrors the approch of most (if not all) heritage railways where the local force is the Policing authority. This may in part be an attempt to cut costs as the BTP is mostly funded by the railway industry itself through levy charged on those who make use of it and unlike regular TOCs, whose trains usually pass though numerous Policing authorities, a small system while within a single Police authority doesn't need the flexibility the BTPs remit provides

[Coryton]

Back in the mountains, I came across this passing loop on the funicular up to the Reichenbach Falls, Meiringen, Switzerland.

 Reichenbach Falls Abtsche Weiche.jpg

 

A bit of research and I discovered that it's known in German as an Abtsche Weiche (roughly "Abt's points"), after the engineer Carl Roman Abt, famous for rack railways. It relies on the "inner" wheels of each car being relatively wide, and having no flanges, and the "outer" wheels having two flanges. Pictures to explain it at the German wikipedia page (no English equivalent that I could find).

 

 

I had great difficulty working out how this design functioned when I first came across it some years ago until I saw an upside down maintenance trolley and all became clear.

[jim.snowdon]

I believe it depends to some extent on the location of the tramway.

 

The first thing to remember is that on sections shared with pedestrians or other motorised vehicles (or where they run alongside the same with no fencing securing the tram tracks from trespassers), trams are treated by law as if they were Buses. Thus trams are fitted with indicators and brake lights as per cars, and if an accident were to occur then it would be processed using motoring driving offences. Such sections do not usually have signalling as such - while their are tram signals associated with facing points and traffic lights, the onus is on the driver of the tram to ensure they can stop in the distance they can see to be clear. It therefore follows that Policing for on road sections is the responsibility of the territorial force concerned - in Manchester's case GMP

 

On segregated fenced in alignments, were the public are trespassing if they go onto the track, then railway rules apply allowing higher speeds combined with a propper signalling system and while this in theory makes the BTP the relevant authority, in practice many operators will probably continue to make arrangements with the local police force instead. This mirrors the approch of most (if not all) heritage railways where the local force is the Policing authority. This may in part be an attempt to cut costs as the BTP is mostly funded by the railway industry itself through levy charged on those who make use of it and unlike regular TOCs, whose trains usually pass though numerous Policing authorities, a small system while within a single Police authority doesn't need the flexibility the BTPs remit provides

As far as the policing authority is concerned, BTP do not have any automatic powers to police tramways, either on or off street; the decision rests with the tramway operator, and from recollection both Sheffield and Manchester use the local police. Croydon Tramlink opted for BTP rather than the Metropolitan, but were under no compulsion to do so.

 

The accessibility or otherwise of off street tramway track depends on whether the trams are being operated under line of sight rules, or as a railway under the control of fixed signals. On general, line of sight tramway is accessible, ie is not required to be fenced, and trespass would be difficult to prove as an offence. Manchester Metrolink operates under railway rules on the Bury and Altrincham lines, and thus where trespass would be enforceable, and in parts, those lines also share alignments with Network Rail and come under their protection as regards trespass. Similarly, the section of Croydon Tramlink between Birkbeck and Beckenham Junction.

 

Road traffic accodents, at least on Tramlink, were dealt with by the Metropolitan Police, not BTP, even on the off-street road crossings.

 

Jim

[DavidBird]

And on the Croydon Tramlink system, at Mitcham, where earlier buttressing to a failing retaining wall precluded normal double track, and interlacing saved two sets of switches and mechanisms.

 

However, the piece de resistance of track interlacing probably has to be this specimen, which was installed on Stuttgart tramway system in 1997. Not only is it a crossover within the interlace, but because Stuttgart were installing dual gauge track as part oftheir phased changeover from metre to standard gauge, it is interlaced dual gauge as well. The crossover is still there, albeit now standard gauge only as the changeover from metre gauge has been completed. There are, to judge by the cab videos on youtube, still quite a few dual gauge junctions still in place on the street sections of the system simply because it is impractical to remove the metre gauge rails other than when the whole junction comes up for renewal.

 

Stuttgart interlace 1.jpg

 

Stuttgart interlace 2.jpg

 

Both pictures appeared in the June 1997 issue of what was then Light Rail & Modern Tramway magazine.

 

Jim

 

What is the purpose of the cross rails in the Stuttgart images?  At first I thought it was a cross-over, as in Re6/6's street tramway picture.  But they seem to be fixed at both ends, so cannot be switch rails...

[jim.snowdon]

What is the purpose of the cross rails in the Stuttgart images?  At first I thought it was a cross-over, as in Re6/6's street tramway picture.  But they seem to be fixed at both ends, so cannot be switch rails...

They are the crossover - what is confusing is that each pair of switches consists of a switch with a moveable tongue and an open switch (or in tramway parlance, a "mate"). Unlike railway practice, where the wheels are always guided by the gauge face of the switch rail, in this example, the back of the (single) switch rail is used to guide the wheels into the turnout (or crossover) route. This arrangement is quite common in tramway practice, usually with grooved rail, and in some respects can be traved back to horse tramways, where neither switch might have a moveable tongue, with the guidance being provided by the pull of the horse in the required direction. This did mean that the horse had to know the route at least as well as the driver.

 

Jim

[phil_sutters]

I have already uploaded this to another thread, but finding this one I thought it might be of interest. A helpful viewer of that thread is fairly sure that it is Ledbury bridge, that is under repair and necessitating the inter-laced formation.

[DavidBird]

They are the crossover - what is confusing is that each pair of switches consists of a switch with a moveable tongue and an open switch (or in tramway parlance, a "mate"). Unlike railway practice, where the wheels are always guided by the gauge face of the switch rail, in this example, the back of the (single) switch rail is used to guide the wheels into the turnout (or crossover) route. This arrangement is quite common in tramway practice, usually with grooved rail, and in some respects can be traved back to horse tramways, where neither switch might have a moveable tongue, with the guidance being provided by the pull of the horse in the required direction. This did mean that the horse had to know the route at least as well as the driver.

 

Jim

 

On looking at the 2nd picture again, I can see the ends of these crossover rails do have different fixings.  That explains the "cutout" in the head of the rail on the left, to allow the flange to pass through the fixed tongue.  I expect the right side switch rail, which we can't see off the bottom of the picture, with the "thick T-shaped" fastenings is a conventional moveable tongue.

 

Thanks Jim.

[Vistisen]

Fascinating stuff Andy.

 

It's a shame that it has been a flop. In theory it looks a very good flexible idea.

 

I have never understood why the trolleybus seems to have never been considered over here as an alternative where new tramways are considered too expensive.

 

It was interesting to see in a recent 'Rail' magazine of the very high public satisfaction ratings of the five or so tramways that we now have. Particularly high was the Edinburgh system despite all the political hatred of it!

 

One word: ROADWORKS. This is what killed the Copenhagen experiment with trolley busses in the 90's

[Coryton]

One word: ROADWORKS. This is what killed the Copenhagen experiment with trolley busses in the 90's

 

Presumably not so much of a problem with a back-up diesel engine or even batteries.

 

Beijing manages very happily with dual mode trolleybuses, and it doesn't require the driver to get out to raise the trolleys when going back on the wires.

[Grovenor]

They are the crossover - what is confusing is that each pair of switches consists of a switch with a moveable tongue and an open switch (or in tramway parlance, a "mate"). Unlike railway practice, where the wheels are always guided by the gauge face of the switch rail, in this example, the back of the (single) switch rail is used to guide the wheels into the turnout (or crossover) route. This arrangement is quite common in tramway practice,

 

On looking at the 2nd picture again, I can see the ends of these crossover rails do have different fixings.  That explains the "cutout" in the head of the rail on the left, to allow the flange to pass through the fixed tongue.  I expect the right side switch rail, which we can't see off the bottom of the picture, with the "thick T-shaped" fastenings is a conventional moveable tongue.

Note that the 'mates' are in the outside rails at each end of the crossover, essential in this case as there is no crossover for the metre gauge so a moving switch in the common rail used by the metre gauge would be a derailment risk for metre gauge cars.

Regards

[Talltim]

Here is a picture of a "threefourway" plus four diamonds that will be the centre of my new shunting plank. It is built entirely from re cycled code 75 N/S bullhead rail and refurbished copper-clad from my previous plank which may explain sleeper lengths, spacing and additional bits of sleepering where none should exist, especially in the diamonds. I don't think a few stray sleepers and oddments here and there matter primarily because I'm the only one who will be looking at it and secondly I don't possess the skills, imagination nor inclination to build a proper working model railway! I just enjoy "mucking about" with them. Incidentally, the two additional diamonds will be be attached to the existing diamonds and the right hand road of another three way whose centre road feeds the four way. Is it prototypical? I haven't a clue, but it's good fun. Anyway, the cod will soon be running! Regards. Serron.

That looks great. Going to be a shunting plank that is out of the ordinary!

[Re6/6]

Another couple of pics found of the 'long not worked upon but one day will be' P4 dock layout centre piece, built using 'Baronrail' fully checkrailed methods

 

All the 'cobbling' was done using good quality grey tiling grout and made with a pin in a pin vice. Again, a 'Baronrail' method.

 

P.S. It is (or was!) fully functional with an 08 traversing nicely everywhere, except strangely through one simple A6 turnout!

 

 

Edited October 1, 2016 by Re6/6

[Pacific231G]

Though fairly simple this formation has fascinated me since I discovered it in the early 1990s.

 

 

It's at Port Bloc at Pointe de Grave at the mouth of the Gironde opposite Arcachon in S.W. France.

 

The purpose seems clear; , to enable wagons to be shunted either very close to the side of the quay or at a more normal distance. Despite my less than brilliant photo you should be able to see in the close up that while most of the inset track on the quay has a normal rail with a much lighter contra-rail the common rail beyond where the crossing/frog would normally be has two rails of equal size that each act as the other's vontra-rall (checkrail more or less) depending on which "half siding" has been used.

 

 

When I first saw it the track on the quayside appeared to have been unused for sometime but it had been part of a particularly interesting system operated until the 1970s or 80s by the Bordeaux Port Authority.(Port Autonome de Bordeaux) mainly to convey sand, gravel and blocks from Port Bloc and a nearby SNCF interchange yard to various sites down the coast as far as Soulac.

 

This line is now use by the PGSV Tourist Railway using "draisines" (motorised PW workers' trollies) starting from a terminus adjoining the SNCF terminus and running for 7kms south west to Soulac. The port authority railway used to be far more extensive at the Port Verton end, crossing the SNCF line to reach Port Bloc in a wide curve with branches to various breakwaters whose repairs it also supplied with materials. However, a couple of sidings also seems to have run into the workshops used to maintain buoys a few hundred metres from the quay. Though I assumed the purpose of the extra quayside half siding was to facilitate the transfer of sand and gravel from barges it occurs to me that it may have been to bring special flat wagons closer to the port authority tenders in order to enable buoys, which are fairly large objects especially when out of the water, to be slid between wagon and deck.

 

Despite a general fascination with quayside lines, I've never come across another formation like this so think it may have served a very specific purpose.  Has anyone come across an arrangement like this anywhere else?

Edited October 1, 2016 by Pacific231G

[Brian Harrap]

Though fairly simple this formation has fascinated me since I discovered it in the early 1990s.

 

pointe de grave pointwork.jpg

 

It's at Port Bloc at Pointe de Grave at the mouth of the Gironde opposite Arcachon in S.W. France.

 

The purpose seems clear; , to enable wagons to be shunted either very close to the side of the quay or at a more normal distance. Despite my less than brilliant photo you should be able to see in the close up that while most of the inset track on the quay has a normal rail with a much lighter contra-rail the common rail beyond where the crossing/frog would normally be has two rails of equal size that each act as the other's vontra-rall (checkrail more or less) depending on which "half siding" has been used.

 

When I first saw it the track on the quayside appeared to have been unused for sometime but it had been part of a particularly interesting system operated until the 1970s or 80s by the Bordeaux Port Authority.(Port Autonome de Bordeaux) mainly to convey sand, gravel and blocks from the Port Bloc and an adjoining SNCF interchange yard to various sites down the coast as far as Soulac.

 

This line is now use by the PGSV Tourist Railway using "draisines" (motorised PW workers' trollies) starting from a terminus adjoining the SNCF terminus and running for 7kms south west to Soulac. The port authority railway used to extend futher, crossing the SNCF line to reach Port Bloc in a wide curve with branches to various breakwaters whose repairs it also supplied with materials. However, a couple of sidings also seems to have run into the workshops used to maintain buoys a few hundred metres from the quay. Though I assumed the purpose of the extra quayside half siding was to facilitate the transfer of sand and gravel from barges it occurs to me that it may have been used to bring special flat wagons close to tenders to enable buoys, fairly large objects out of the water, to be slid between wagon and deck.

 

Despite a general fascination with quayside lines, I've never come across another formation like this so think it may have served a very specific purpose.  Has anyone come across an arrangement like this anywhere else?

I thought I'd done with all the trackwork I was going to do on QUAI:87. Might have to incorporate something like this. B

[RJS1977]

One word: ROADWORKS. This is what killed the Copenhagen experiment with trolley busses in the 90's

 

I've often wondered about the possibilty of an "electro-diesel" (or electro-ethanol) trolleybus picking up off trolley wires where available and running off a generator the rest of the time (like a Class 73) - primarily to enable municipal routes to be wired whilst longer routes use the wires when they can, but it would also enable trolleybuses to be diverted easily.

[micknich2003]

I've often wondered about the possibilty of an "electro-diesel" (or electro-ethanol) trolleybus picking up off trolley wires where available and running off a generator the rest of the time (like a Class 73) - primarily to enable municipal routes to be wired whilst longer routes use the wires when they can, but it would also enable trolleybuses to be diverted easily.

I'm pretty sure it's either been done or is on the "Drawing Board".

[Fat Controller]

I'm pretty sure it's either been done or is on the "Drawing Board".

There were Berliet/ Renault vehicles using electro-diesel technology in Lyon 30+ years ago- they'd use trolley wires in the city, then diesel out-of-town. There were also pure diesel and pure electric vehicles using the same body design.