Interlaced or gauntlet track

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MarkyT

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It seems a bit odd to have the tracks interlaced in 1901, particularly as there are houses on the south side. The building on the north side may be a business, but would the tracks been interlaced to avoid inconveniencing one business?
While there weren't many motor cars and lorries around at the time (some steam cars and wagons though), there must have been other traffic. Even if everyone didn't have their own horsedrawn vehicles at home, there would have been deliveries, etc. According to the old map, the buildings north of Rugby Road don't look residential but are unlabelled, so there could have been a works/depot entrance which needed to be kept clear for a queue of incoming vehicles, or rather the queue that would form regardless would block tram services otherwise.
 
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Whisky Papa

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It seems a bit odd to have the tracks interlaced in 1901, particularly as there are houses on the south side. The building on the north side may be a business, but would the tracks been interlaced to avoid inconveniencing one business?

I seem to remember reading that tramway companies were responsible for the upkeep of the roadway between the rails and a certain width either side - 18" springs to mind but I could well be wrong. If this line had been built by the commercial operator before Portsmouth municipalised them, could it have been an economy measure, particularly if it was not a line that was intended to see heavy use? However, the plaque referred to in #58 suggests it was laid in 1901, which is when the city council took over, so possibly a tad too late for that scenario - unless the same economy would have been relevant to the city council too?
 

MarkyT

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Much of the initial network of the early 20th-century narrow gauge tramway in Torquay was single track, with spring points at passing loops I believe. The streets it negotiated were of varying widths with steep gradients and tight bends in places. The town centre core and the spur from the harbour to the railway station along the seafront main road was double throughout, however, as was the extension to Paignton a few years later.
 

geoffk

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There are indeed four rails.
But mixed 5' 3" and standard gauge appears to be acceptable as a three-rail layout in Australia. One platform at Melbourne Southern Cross station has this arrangement as it's used by the local 5' 3" Vic Rail trains and the twice-daily XPT from Sydney, which is standard gauge. Of course the common rail has to be next to the platform. But I don't know if any running lines work on this basis. Worth mentioning just in case Boris Johnson's tunnel under the Irish Sea comes about and the line from Larne to Belfast has to be "mixed"!
 

zwk500

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But mixed 5' 3" and standard gauge appears to be acceptable as a three-rail layout in Australia. One platform at Melbourne Southern Cross station has this arrangement as it's used by the local 5' 3" Vic Rail trains and the twice-daily XPT from Sydney, which is standard gauge. Of course the common rail has to be next to the platform. But I don't know if any running lines work on this basis. Worth mentioning just in case Boris Johnson's tunnel under the Irish Sea comes about and the line from Larne to Belfast has to be "mixed"!
The 6.5" difference between the inner faces of the rails in that combination is big enough to allow the fastenings for the inner rail onto the sleeper. The post you quoted is talking about 3.5" difference, which does not. Therefore to get the gap between the rail large enough, 4 rails have to be used. On the wiki article about rail gauge there's a great diagram showing how 4 rails can facilitate something like 5 different commonly-used rail gauges.

None of Boris's waffle will come to any greater effect than the Thames Estuary Airport or the Garden Bridge. If a fixed link to Ireland is built, I suspect we would see a new standard gauge line built into a city-centre terminal (either Dublin or Belfast depending on the option) and passengers expected to transfer. We could see other solutions, variable-gauge axles as per the Spanish being more likely than 3-rail track, but anything is possible.
 

geoffk

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The 6.5" difference between the inner faces of the rails in that combination is big enough to allow the fastenings for the inner rail onto the sleeper. The post you quoted is talking about 3.5" difference, which does not. Therefore to get the gap between the rail large enough, 4 rails have to be used. On the wiki article about rail gauge there's a great diagram showing how 4 rails can facilitate something like 5 different commonly-used rail gauges.
railroaded.jpg Illustration of four-rail layout on North Korea - Russia border.
 

zwk500

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Illustration of four-rail layout on North Korea - Russia border.
That's 1,435mm and 1,520mm mixed, each having a separate pair of rails. The 4-rail multi gauge I was thinking of is actually this one from Australia (It's only 3 gauge though):
1614609997459.png
 

geoffk

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If this is a passenger line, what happens at station platforms?! I assume the three tracks must separate.
 

zwk500

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If this is a passenger line, what happens at station platforms?! I assume the three tracks must separate.
I don't know, tbh. From what I can gather this setup is primarily used in yards, the passenger lines tend to terminate at the break-of-gauge station.
 

D365

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There is a tiny amount of interlaced track on Sheffield Supertram, mainly around Hillsborough. In all instances, this is to avoid pointwork on streets.
 

XAM2175

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But mixed 5' 3" and standard gauge appears to be acceptable as a three-rail layout in Australia. One platform at Melbourne Southern Cross station has this arrangement as it's used by the local 5' 3" Vic Rail trains and the twice-daily XPT from Sydney, which is standard gauge. Of course the common rail has to be next to the platform. But I don't know if any running lines work on this basis.
Yes, the three-rail SG+BG arrangement is used on a few running lines in Victoria - about 30 km in total, off the top of my head. If I recall correctly there is also a requirement to use a narrow-headed rail on the BG outer, and/or impose a moderate permanent speed restriction on the BG line due to the risk of debris becoming jammed between the two outer rails.
 
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