Bullhead and flat bottom track

[cromptonnut]

I'm sure the answer is easily found but I can't seem to locate it, and am sure one of you guys will have it readily to hand.

 

Simply, when did flat bottom rail become 'standard' on lines throughout the UK? 

 

My layout is a secondary main line (singled and rationalised) set in the south west in the 1980's.

 

I think I need flat bottom on the main lines and can use bullhead in the sidings/bays/loops/older areas (no doubt the two were seen alongside in a number of locations) but would appreciate confirmation.

[Trog]

Mid 1950's for mainlines, a little later out in the sticks. By the 1980's relaying in Bullhead track would probably only be done with serviceable material in sidings and on the most minor of running lines.

[Nick Holliday]

Despite all the pointwork for the junction being recently replaced using concrete bearers, the down Epsom Downs platform at Sutton is still laid with bullhead rail, but this may be due to the need to have a continuous check-rail!

[cromptonnut]

Thanks for the replies - flatbottom it is then

[Pandora]

Bullhead rail is very flexible, ask any railway slinger who has to load the stuff onto a bogie wagon,  they detest bullhead rail!

 

 Bullhead will therefore be found where sharp curves are required say 200 to 300 metre radius,  200 meters radius being  to most purposes the  tighest curvest outside yards and sidings, eg a spur making a triangle between two other lines,  the line speed may well be only 10 to 20 mph negotiating a 200 metre radius curve.

 

A benefit is bullhead rail has four wear faces compared to two for flatbottom, so bullhead can be inverted in the sleeper chairs or transposed  from cess to six foot side etc. theoretically  doubling life compared to flatbottom, the reality is neither bullhead or flat bottom rail is ever inverted or transposed, once worn on the first face,  it is replaced with new, like for like.

Edited March 18, 2013 by Pandora

[Nick Holliday]

A benefit is bullhead rail has four wear faces compared to two for flatbottom, so bullhead can be inverted in the sleeper chairs or transposed  from cess to six foot side etc. theoretically  doubling life compared to flatbottom, the reality is neither bullhead or flat bottom rail is ever inverted or transposed, once worn on the first face,  it is replaced with new, like for like.

Only in the very early days of railways did they consider being able to turn the rail over as a way of extending its life, with some original rail section being a true double head.  Experience soon showed that the impact upon the bottom of the rail at each chair created indents that made that surface totally unsuitable as a running rail, so the section was redesigned with the smaller section for the base, allowing for wear only on the top half, and saving on the overall weight.

[HSB]

I seem to recall quite a few lengths of Bullhead still around in South Devon in the 80s.

[Siberian Snooper]

A benefit is bullhead rail has four wear faces compared to two for flatbottom,

The head of Bullhead rail is of a different section to the foot, so it only has two wear faces as per flat bottom. If the head of the rail was worn enough to fit in a chair it would have been scraped long ago.

 

SS

[Trog]

Rail is sometimes still transposed, provided the line speed and the remaining head width meet the set standards.

 

As for using BH on tight curves, the rails should be pre-curved before installation in these situations. So the flexibility of the rails is irrelevant.

[Ramblin Rich]

I seem to recall quite a few lengths of Bullhead still around in South Devon in the 80s.

 

There still was on the Barnstaple line late last year - this was near Lapford in October 2012

 

 

 

I believe this area is being relaid at present though...

Edited March 18, 2013 by Ramblin Rich

[micknich2003]

Is Bullhead rail still rolled? Mick.

[Pandora]

Rail is sometimes still transposed, provided the line speed and the remaining head width meet the set standards.

 

As for using BH on tight curves, the rails should be pre-curved before installation in these situations. So the flexibility of the rails is irrelevant.

 

Is this a local practice in the area where you work?  I have never ever seen rail pre-curved,  how can you transport it to site?

 

 I have changed plenty of rail in my time,  as a crane driver,  we load  6 x 60 ft lengths on the sides of a Tramm, lift out the old and then drop the new into the chairs, even on 200 meter curves.

[Pandora]

Only in the very early days of railways did they consider being able to turn the rail over as a way of extending its life, with some original rail section being a true double head.  Experience soon showed that the impact upon the bottom of the rail at each chair created indents that made that surface totally unsuitable as a running rail, so the section was redesigned with the smaller section for the base, allowing for wear only on the top half, and saving on the overall weight.

 There was a section of line between Continental junction and Folkstone,  I think it was Bullhead and I think it may have been inverted at some point as the top was corrugated.

it was a nightmare to drive a train over it,  thankfully it was replaced about 2 years ago

[Nick Holliday]

A trip on the District Line to Ealing Broadway has reminded me that substantial parts of the London Underground system use bullhead rail.

[cromptonnut]

The Peco range of flat bottomed track seems to be limited to two points and flexitrack, nothing else which is a little frustrating.  Also it seems that very few shops actually stock it.

[uax6]

Is Bullhead rail still rolled? Mick.

 

I belive that Bullhead is still rolled for use in Scotland, why flat bottom rail isn't used in preferance to BH I have no idea!

 

Funny enough there is a small length of BH sat in the cess outside the box here. It's use? Used for lifting bridge timbers on our bridge in january, and still not recovered!

 

Andy G

[Merfyn Jones]

I belive that Bullhead is still rolled for use in Scotland, why flat bottom rail isn't used in preferance to BH I have no idea!

 

Funny enough there is a small length of BH sat in the cess outside the box here. It's use? Used for lifting bridge timbers on our bridge in january, and still not recovered!

 

Andy G

 

And not just in Scotland.

In many places rail is renewed rather than relaying track where the sleepers have usefull life left.  A large part of the Llandudno branch was done recently, replacing 45 ft. lengths with 60 ft.  Makes you think the train is going slower !

Merf.

[Coach bogie]

still around on Teesside

 

Mike Wiltshire

[uax6]

Heres some photos I took last night to illustrate the change in Bullhead profile:

 

This is an old length that was converted to hold a gate back:

The worn surface is on the right.

 

This is the end of the 'new' BH:

Look how much bigger the head is compared with the foot, there's no way you could turn this over!

 

 

Andy G

[Southernman46]

The new stuff is BS95 BH rail - still a valid spec and very much in use today

 

The old stuff is bullhead but probably a particular vintage "company" design - interesting

[Ncarter2]

Is this a local practice in the area where you work? I have never ever seen rail pre-curved, how can you transport it to site?

 

I have changed plenty of rail in my time, as a crane driver, we load 6 x 60 ft lengths on the sides of a Tramm, lift out the old and then drop the new into the chairs, even on 200 meter curves.

Sorry only just came across this. Curves these tight should have pre curved rails, when not it makes it very difficult to get a nice curve profile and often it ends up with unnecessary lateral force at the fish plates causing the 50p effect.

[Trog]

50p effect is a flatbottom rail problem, bullhead being an older section suffers from threepenny bit effect instead. 

 

In both cases rails laid in too tight a curve without being pre-curved to that radius tend to straighten out under traffic, giving a series of rail long curves shallower than the average radius of the curve with the difference being made up by corners at the fish plated joints.

 

 

Also 95lb BS bullhead rail has not been rolled since the standard was updated in 1924, the new stuff being of the 95lb RBS section. /[Pedant Mode]

[E3109]

I've seen brand new bullhead rail waiting to be installed, in a couple of locations where I work. So it's certainly still rolled.

I would imagine that costs play a part, i.e. Do you relay the entire siding with flat bottom BS110 or whatever, or do you buy a small amount of 'obsolete' rail (at premium prices presumably), in order to fit in with the layout you wish to rehabilitate.

[CazRail]

We still re-rail bullhead all the time, a lot of it around Machynlleth's area.

[Trog]

We still re-rail bullhead all the time, a lot of it around Machynlleth's area.

 

If the sleepers and ballast are sound re-railing in bullhead so reusing the existing sleepers, chairs and ballast is an economically sensible option for lightly used lines.

 

One step up from this where you need to re-rail and upgrade quite a lot of bullhead in a hurry and possessions are hard to come by, is to also change the chairs to M-AS1-P baseplates. You can then re-rail in flat bottom CWR the conversion process is aided by the fact that the baseplate reuses two of the three screw holes left by the removed AS1 baseplate. This gives a light weight CWR that needs extra precautions taking in hot weather, but improves the ride and reduces the maintenance burden by eliminating the joints.