Trivial Question - the 6 Foot

[grumpyxch]

The 6 Foot - is it actually 6 feet, or what size is it? Is it measured between the two nearest rails on adjacent tracks or is it the distance between two lines of sleepers?

 

[swt_passenger]

Mr Ellis’s encyclopaedia says it really is 6ft, or 1830mm. Measured between outside edges of the rails

 

[Mcr Warrior]

Mr Ellis’s encyclopaedia says it really is 6ft...

...Measured between outside edges of the rails

Otherwise be a little difficult to fathom how to measure it!

 

[pdeaves]

It's typically 6' but varies (e.g. going round a bridge pier).

 

[John Webb]

It should also be noted that on quadruple track (and further multiple lines) there may be a '10ft' gap between each pair of lines; this was a previous Board of Trade requirement. Most sidings will also be laid at least 10ft from the nearest running line as well.

 

[grumpyxch]

I would write "they go ROUND bridge piers?" but you might think I was being serious. I assume then that 6 feet is the minimum spacing, though I seem to remember that a few years ago, the Hastings line (which had a narrow loading guage so used narrow stock) increased the gap up to at least 6 feet where they could, and controlled access where they couldn't, so they could use 'normal' width stock without having collisions as trains pass. However, the reason I asked the question in the first place was that I had just watched one of those "Hornby Model World" programmes on the tv, and it showed a model railway where the modeller had gone to extreme lengths to get his model (based on a real place) accurate. The tracks though appeared to be to the normal 'OO guage model railway' 6 foot - that is, too wide - though admittedly OO scale is 4mm to the foot while OO track guage is not. OO model railways never seem to get that 6 foot right (or is that just me being wrong?).

 

[plugwash]

It should also be noted that on quadruple track (and further multiple lines) there may be a '10ft' gap between each pair of lines;

Am I right in thinking that the idea behind this was that each track should have a "safe" side where the crew of the train can walk down the outside of the train safely?

 

[norbitonflyer]

The tracks though appeared to be to the normal 'OO guage model railway' 6 foot - that is, too wide - though admittedly OO scale is 4mm to the foot while OO track guage is not. OO model railways never seem to get that 6 foot right (or is that just me being wrong?).

Two factors about OO -
Firstly, the track gauge is too narrow - 16.5 mm track gauge was originally designed for 3.5mm to the foot scale models (HO gauge, 1:87, widely used in the US and Europe), but motors built for HO models would not fit British locomotives built to that scale, so they were designed to a larger scale, 4mm to the foot, 1:76 (OO - or Dublo), but using the same 16.5mm track as HO. At 4mm to the foot, 16.5mm track gauge scales to 4' 1.5", seven inches narrower than Stephenson gauge. To keep the track centres the right distance apart you would therefore need to widen the "Six Foot" to 6'7"

Secondly, the curves are much tighter on most model railways than you would ever see in real life, which means that there is greater "throwover" on curves. To avoid long vehicles hitting each other, the track spacing has to be wider, at least on curves. This is not a factor if you are modelling a real place to scale, as the curves will also be to scale.

 

[Dstock7080]

delete

 

[2192]

Some British trains could do 140mph but they are restricted to 125mph because the six foot would need to be wider. The ride quality would be bad when passing trains coming the other way.

 

[furnessvale]

The tightest "6ft" I ever personally measured was 4' 8" at Bullgill on the Maryport and Carlisle Railway.

Hence the need for bars on the drop windows of Mk1 DMUs.

 

[norbitonflyer]

"the six -foot clearance between the EB and WB roads in the area of the incident should have been at least 1910mm."

We all know what that means, but it reads as if metric/imperial conversion factors are variable, like currency exchange rates!

1910mm is actually more than 6'3" . 6 feet is not quite 1829mm

 

[Dstock7080]

We all know what that means

apologies, I’ve removed my unhelpful post

 

[John Webb]

Am I right in thinking that the idea behind this was that each track should have a "safe" side where the crew of the train can walk down the outside of the train safely?

I don't know - my source is "Railway Signalling and Track Plans" by Bob Essery* (Ian Allan, 2007) where he has copied a table of the minimum spacings from a permanent way publication, but gives no reason for the 10ft except it was a BoT requirement. There would also need to be space for signals and other necessary items, of course, and to give space to workman on one pair of lines when the adjacent line(s) remained in use.

*As a footnote I have learnt that Bob Essery died recently.

 

[O L Leigh]

I've always had the impression that the term "6 foot" is primarily a colloquialism rather than a specific measurement; likewise "10 foot". In much the same way as the "4 foot" not being 4 feet, the 6 and 10 foot can be almost any distance and yet the term is applied universally. Indeed, in some former broad gauge areas, such as Gloucester to Severn Tunnel Junction via Lydney, the 6 foot can be significantly larger than the stated measurement. That there are minimum measurements to ensure the safe running of trains and adequate clearance for lineside objects is certainly the case, and that perhaps does help to explain the origin of the terms.

 

[themiller]

I don't know the actual dimension but the two track section of the WCML between Lancaster and Preston has a section which is considerably greater than 6' for several miles.

 

[Wilts Wanderer]

Some British trains could do 140mph but they are restricted to 125mph because the six foot would need to be wider. The ride quality would be bad when passing trains coming the other way.

This is not true.

 

[PeterY]

I've seen some very narrow stations and the one that springs to mind is St Leonards Warrior Square. The rails seem very close to each other. So, if it's called the 6' what is the absolute minimum?

 

[plugwash]

Just doing some back of the envelope calculations.

I'm struggling to find good information on the open internet about what exactly the gauges of UK trains are, but assuming the labels on page 16 of http://web.archive.org/web/20110929...rastructure/Guidance Notes/GEGN8573 Iss 3.pdf represent distances from rail center then it looks like a train can be up to 1400 mm from rail center. The track gauge is 1435mm total or about 717mm from rail center. so that essentially leaves about 683mm or about 2.25 feet of overhang on either side. So a 6 foot spacing between adjancent lines would leave about a foot and a half of space bettween trains on adjacent lines.

Which does seem to me that it would be too close to walk safely alongside a stopped train while the adjancent line was active. Whereas 10 feet would give about 5 and a half feet of space which sounds much safer to walk down.

 

[30907]

I've seen some very narrow stations and the one that springs to mind is St Leonards Warrior Square. The rails seem very close to each other. So, if it's called the 6' what is the absolute minimum?

Interesting, it looks less than 6ft (even allowing for the third rail).

Over-simplifying, because these days they talk of "envelopes" to allow for swaying etc, but it needs to be sufficient for 2 standard coaches to pass without touching - that's about 5ft on dead straight track at low speed.

 

[snowball]

Which does seem to me that it would be too close to walk safely alongside a stopped train while the adjancent line was active.

I believe the advice if a train comes at you on the other line is to lie down.

At least if it isn't a third rail area.

 

[grumpyxch]

PeterY - Isn't St. Leonards Warrior Square on the line from London to Hastings? I believe that line was built with less than the normal space between the two tracks, which meant they had to have slimmer trains, hence the Hastings Units and the special version of the Class 33 diesel, both of which were built specially for that line. Normal width locos and rolling stock were banned from that route. They tried to solve the problem about 20 years ago by separating the tracks where they could and preventing both lines being used at the same time in those places where they couldn't separate them. That way they could use normal width trains (until something goes wrong). The drivers would know where the narrow bits were, and, I assume, would use their sense of self-preservation to not take risks if something looked iffy. After all, they were at the front which would be the first bit hit if another train got too close

 

[30907]

PeterY - Isn't St. Leonards Warrior Square on the line from London to Hastings? I believe that line was built with less than the normal space between the two tracks, which meant they had to have slimmer trains, hence the Hastings Units and the special version of the Class 33 diesel, both of which were built specially for that line. Normal width locos and rolling stock were banned from that route. They tried to solve the problem about 20 years ago by separating the tracks where they could and preventing both lines being used at the same time in those places where they couldn't separate them. That way they could use normal width trains (until something goes wrong). The drivers would know where the narrow bits were, and, I assume, would use their sense of self-preservation to not take risks if something looked iffy. After all, they were at the front which would be the first bit hit if another train got too close

The restriction you mention only applies north of Bopeep Junction.

I imagine the station has "grandfather rights" - an interesting example is Okehampton where the former down platform can apparently no longer be used because the reopened up line has to conform to current clearance rules.

 

[75A]

The narrowness on this line was mainly in some of the tunnels which had to be relined due to poor construction. When the line was electrified the tunnels were reduced to single line.

 

[Annetts key]

In terms of staff safety, the current rules mean that the ‘ten foot’ is unlikely to be considered to be a safe position. Staff have to be at least two metres (6’ 6”) from any open line.

When working with lookout protection, if the linespeed is 100MPH or below, the position of safety can be reduced to 1.25 metres (4’) from the nearest open line.

All distances to a line mean the nearest edge of the nearest running rail (as far as the rules are concerned).

 

[Ploughman]

South of York station the 4 track section to at least opposite Tesco has the spacings reversed.
The 6ft's are about 10ft and the 10ft's are near 6ft.

Also up near Monkwearmouth Sunderland it was theoretically possible to run a train on the 6ft rails for a reasonable distance 1/2 mile or so, back in the 90's.

 

[Gloster]

Supposedly the contractor building the Hastings line saved money by lining the tunnels with fewer rings of bricks than was required by the contract. Fairly early on there was a fall and, because of the cost and difficulty of widening the tunnel internally, more rings of bricks were added inside those originally provided by the contractor. This unfortunately impinged on the loading gauge and resulted in dedicated stock up to the 1980s. (There have been other explanations, but this seems to be basically accurate.)

 

[mmh]

I believe the advice if a train comes at you on the other line is to lie down.

At least if it isn't a third rail area.

There was a terrifying video of, I believe, an East Coast driver doing just that with seconds remaining when he believed the line was blocked, but wasn't, in the past few years.

 

[etr221]

I understand there were (are) some quadruple lines (I think Euston-Roade is a significant one) where there are three '6 foot's, rather than two and a '10 foot' between them - result of parsimony when the quadrupling was done.

 

[Dr Hoo]

I understand there were (are) some quadruple lines (I think Euston-Roade is a significant one) where there are three '6 foot's, rather than two and a '10 foot' between them - result of parsimony when the quadrupling was done.

Probably more that the need for an intermediate 'place of safety' wasn't really recognised at the time. With far fewer trains and much lower speeds there was little chance of getting 'caught in the middle'.