Width of the 'six foot'

[Re6/6]

Can anybody let me know please the actual/usual distance between the outside rails on British double track? I assume that there's a standard. I'm looking at GWR, BR steam and modern era.

 

Thanks

 

John

[Bomag]

Can anybody let me know please the actual/usual distance between the outside rails on British double track? I assume that there's a standard. I'm looking at GWR, BR steam and modern era.

 

Thanks

 

John

 

The simple answer is 'it depends'. There is a whole range of conditions which affects the actual cross section; on all schemes I did trying to get straights 'straight' and maintaining clearences to fixed points was much more important that haveing any consistency of six foot dimentions. RCE Anglia in 1989/1990 used a nominal 1830mm between outside edges with minimum of 1800mm unless a lower figure was designed and agreed in advance.

 

The GWR/WR had a 10 foot on old wide gauge lines but as before clearence to plarforms etc governed exact separation. Some WR routes seem to have had the six foot reduced; it make the cess easier to maintain and more importanlty in the 1980s/90s some of the twin jib self propelled cranes used for moving track pannels had capacity limits with fully extended jibs.

[Edwin_m]

The old six-foot is effectively a minimum, laid down in the railway safety principles and guidance which are now on the rail regulator website.

 

As suggested it can be wider especially on former GWR routes. This makes it safer and easier when work is being done on one track while the other one remains open. If you look at the line between Bolton and Lostock this was formerly four tracks but the remaining two have been moved across to a wide spacing. This may be to do with engineering access and also to help with future electrification (thought to be likely about 25 years ago when they did this, I won't comment further).

[Caledonian]

The short answer is not to get confused by dimensions because the terms 4 foot; six foot; and 10 foot are simply geographical terms used to refer to the location of something or some-one and not to be taken literally. EG: he was walking in the 6 foot. While the latter is a theoretical minimum it can be narrower - at South Gosforth Station the 6 foot is actually four foot eight and three quarters, due to the combination of a restricted site and an engineer with a wicked sense of humour. Elsewhere it can be very wide indeed and pieces of string come to mind...

[APOLLO]

From the book "The Wigan Branch Railway" (D Sweeney).

 

At a meeting of the board of directors for the Wigan Branch Railway (Parkside - Liverpool & Manchester Rly to Wigan - now part of the West coast main line) in December 1830, the engineer, Vignoles was instructed to furnish an estimate for the New Springs branch - Ince Mill to New Springs (Wigan), and at this same meeting, the distance between running lines, the way, was fixed at 6 feet. However, at the next board meeting, perhaps with Huskisson's accident at Parkside in mind, it was decided to increase this to 6' 6". The board met again twice in April 1831, and after much debate, finally decided on the 6 foot "way".

 

Brit15

[Gwiwer]

There is no fixed "six feet of separation" as others have noted.

 

The nominal width between the rails increases on curves to allow for the increased overhang of vehicles as they negotiate the curve and, by logical extension, the sharper the curve (i.e. the smaller the radius) the greater the amount of track separation which will be required to maintain the clearance. That is not always observed in practice however since sharp curves are often subject to very low speed restrictions which can mean lesser clearances are acceptable. Basically the "kinematic envelope" (or window) is smaller the lower the permitted line speed so it is possible to find sharp curves with closely-spaced tracks where coach ends come quite close to each other as trains pass. Arundel Junction towards Littlehampton is one of many such examples.

 

In some cases the engineer has permitted specific exemptions to normal spacing and clearances such as on the Tunbridge Wells - St. Leonards route where - in theory - vehicles could come into contact if trains passed each other with both under the extreme of adverse conditions; the kinematic envelopes do not overlap but there is no space between them.

 

Modern track geometry also uses superelevation (cant) to assist trains around curves at higher speeds than would be permitted were the tracks flat. When two tracks are independently canted there can be a reduction in the "six foot" as well because vehicles will not be passing each other with the widest parts of their bodies adjacent. To see this effect on the workbench simply take two coaches, hold them side by side one in each hand and tilt them slightly. The same can be true on high speed lines where tilting trains operate though does not necessarily apply to lines where tilting and conventional trains share the same tracks.

 

There are many variables which come into play and the answer to the OP really is "how long is a piece of string?"

[StaffsOatcake]

The short answer is not to get confused by dimensions because the terms 4 foot; six foot; and 10 foot are simply geographical terms used to refer to the location of something or some-one and not to be taken literally. EG: he was walking in the 6 foot. While the latter is a theoretical minimum it can be narrower - at South Gosforth Station the 6 foot is actually four foot eight and three quarters, due to the combination of a restricted site and an engineer with a wicked sense of humour. Elsewhere it can be very wide indeed and pieces of string come to mind...

 

 

 

Good job they don't have windows you can get your head out of on those trams then.

 

Do the usual rules apply to tramways such as the tyne and wear metro system?

 

 

[Donw]

If your question is related to building a layout you will find that our tighter curves require extra spacing. In order to maintain standard geometry settrack usually maintains the track spacing on straights and curves hence the rather wide spacing on straights. Flexitrack or handbuilt will allow you to increase the spacing on curves whilst maintaining the spacing through the straight stretches.

Also don't forget there was a wider spacing between sidings and the main lines and sidings. In model form you may need to get your fingers between adjacent vehicles (heaven forbid?) usually ok in gauge 0 but more of a problem in N.

DonW

[Re6/6]

Thanks all.

[Edwin_m]

Good job they don't have windows you can get your head out of on those trams then.

 

Do the usual rules apply to tramways such as the tyne and wear metro system?

 

Tyne and Wear is not a tramway. The stock may be slightly narrower at its widest point, and the kinematic envelope will also be narrower in a station because the speed is restricted for non-stopping trains. And as pointed out there is no stock where the passengers can lean out. Between them these factors will allow some reduction in the six-foot without any reduction in safety.

 

The clearances for tramways are set out here. However these depend very much on the size of the vehicles used on a particular network.

[Oldddudders]

Just a thought. The OP was asking about the prototype, for which most of the facts now seem to have been exposed. Those of us who model in OO, with only 16.5mm of 4-foot way, need to allow slightly more 6-foot way because our trains are actually a bit narrow gauge, so the kinematic envelope mentioned by Gwiwer is effectively a bit bigger all round, relative to the rails. End-throw and side-throw on curves needs measuring with a couple of your longest vehicles before you commit to the precise alignment.

[Caledonian]

Tyne and Wear is not a tramway. The stock may be slightly narrower at its widest point, and the kinematic envelope will also be narrower in a station because the speed is restricted for non-stopping trains. And as pointed out there is no stock where the passengers can lean out. Between them these factors will allow some reduction in the six-foot without any reduction in safety.

 

Perfectly true, and its also worth adding that the track layout in question goes back to North Eastern Railway days and has on occasion seen some very big beasties coming through

[StaffsOatcake]

The layout at South Gosford has been change slightly. The platforms have been raised to standard 'Metro' height and and to comply with modern standards (1970's) required that width of the platform was increased so the new concrete edges are in front of the original platform edge encroaching in the usual envelope/loading guage and hence the narrower gap in the '6ft'.

 

 

And also the narrow width of the stock means that the whole of the metro is not subject to the standard national railway standards of the minimum 6ft gap.

[Grovenor]

Everyone has pointed out the exceptions to the rule but to get back to the original question, the great majority of double track lines in the UK were and are built to the standard 6ft way.

Note that this is measured between the outside edges of the rails, not the running edges. So to arrive at the track centre to centre spacing (which is more appropriate if you are modelling in a non-scale gauge) you need to add the 6ft, the 4ft and twice the width of the rail, ie. 6' + 4'8.5" + 2.75" + 2.75" = 11'2"

Regards

[martin_wynne]

the great majority of double track lines in the UK were and are built to the standard 6ft way. Note that this is measured between the outside edges of the rails, not the running edges.

Hi Keith,

 

Note that for GWR and BR(W) it was measured to the running edges - 6ft-6in minimum spacing to gauge faces. (This was a legacy of the old 3" wide rail section used at 6ft way.)

 

This means that the minimum centre-to-centre is 11ft-2.1/2in for GWR and BR(W).

 

i.e. GWR tracks were half an inch further apart than all the others. In 4mm scale that's 44.83mm instead of 44.67mm.

 

regards,

 

Martin.

[Portchullin Tatty]

Remember that some of the GW lines would have formerly been broad gauge.

 

When these were converted, many (most?) kept the same location to the outside of the two lines - they had to otherwise the passengers had to leap from the platforms to the carriages. I suspect that there is still a legacy of this in some locations?

 

Not part of your original posting, but on the Dingwall and Skye Railway, most of the passing points had very wide spacing between the passing loops. This was allow trains to pass carrying the fishing fleet from the Moray Firth to the Atlantic. It is doubted that this ever occured but Garve, Achnasheen and Strathcarron still have quite widely spaced lines even now as a result of this.

[The Stationmaster]

Remember that some of the GW lines would have formerly been broad gauge.

 

When these were converted, many (most?) kept the same location to the outside of the two lines - they had to otherwise the passengers had to leap from the platforms to the carriages. I suspect that there is still a legacy of this in some locations?

 

 

Yes - posted some pics on the last version of RMWeb and still have them if folk are interested, the difference is very noticeable.

[Pugsley]

Yes - posted some pics on the last version of RMWeb and still have them if folk are interested, the difference is very noticeable.

Yes please Mike, I, for one, would like to see them. B)

[Richard E]

Also, in places, according to one of my contacts the 6' can be as little as 4' with bi-directional running still going on. Also, in other places the track has been interlaced to a greater or lesser degree to save width and works on a single line basis but without any points or crossings as there simply isn't space for traffic to pass yet it retains it's own track in each direction.

[Fat Controller]

Yes - posted some pics on the last version of RMWeb and still have them if folk are interested, the difference is very noticeable.

If you want to see a comparison of the relative size of the "6'" on broad-gauge/standard gauge, I would suggest a visit to Severn Tunnel Junction. The old route via Gloucester was broad-gauge, whilst that via the Severn Tunnel was built to standard-gauge norms. The contrast is quite noticeable.

[jamie92208]

Just for info I believe that the distance between a running line and a siding should be 10'.

 

Jamie

[martin_wynne]

Just for info I believe that the distance between a running line and a siding should be 10'.

Hi Jamie,

 

Yes that's correct, also for running loops as well as sidings. Although 9ft is allowed where space constraints make it unavoidable.

 

You can't have more than 2 tracks spaced at 6ft way. For multiple tracks the minimum spacings should alternate 6ft way and 10ft way. So for a 4-track main line that might be a central 10ft way with double tracks each side spaced at 6ft way. Or a central double track spaced at 6ft way, and loops or slow lines each side spaced at 10ft way. This depends on the way the up and down lines are split and the relevant company practice.

 

The problem with a topic such as this is that a proper answer to the OP's question involves writing a book.

 

regards,

 

Martin.

[The Stationmaster]

 

You can't have more than 2 tracks spaced at 6ft way.

regards,

 

Martin.

 

 

As it happens Martin you can. BUT (and yes, it really is a big BUT) there then have to be restrictions on staff access and normally any work, including patrolling, can only be carried out under the cover of a possession or possession of part of the layout. Hence such arrangements tend to be pretty rare (they are rarely found in older track layouts as they required special dispensation) but they do happen occasionally in modern work where space is at a premium and additional lines have to 'squeezed in'.

[martin_wynne]

As it happens Martin you can. BUT (and yes, it really is a big BUT) there then have to be restrictions on staff access and normally any work, including patrolling, can only be carried out under the cover of a possession or possession of part of the layout. Hence such arrangements tend to be pretty rare (they are rarely found in older track layouts as they required special dispensation) but they do happen occasionally in modern work where space is at a premium and additional lines have to 'squeezed in'.

Thanks Mike. I did say that a full reply means writing a book.

[The Stationmaster]

Thanks Mike. I did say that a full reply means writing a book.

 

 

Exactly so Martin but researching all the 'exceptions' and 'differences' and then explaining them would probably mean more than one volume