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How is track laid?


vac_basher

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After having a look on Google, where I wasn't able to find anything relevant to my interests, I thought there must be no better place to ask than here! ;) So my question is, what was the process of track laying in the late 1980s - early 1990s.

What exactly was involved? Obviously a ballast bed would be prepared (but how? How do they get the ballast on site? And then would they manipulate it with rail mounted diggers or with road going JCB type machines?).

Then how were the actual rails and sleepers be put in place? I think, but I'm not sure, that nowadays the sleepers and rails arrive already assembled, but back then were the sleepers laid down first (manually?) and then the rails added? Was it the norm for sleepers and rails to arrive by rail or road?

I'd immagine that then when the sleepers and rails are in-situ a ballast train would deposit a load of ballast over it to keep it all in place, correct?

And finally, what is a tamper machine used for?

Any photos would be greatly appriciated too.

Thanks in advance :)

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What exactly was involved? Obviously a ballast bed would be prepared (but how? How do they get the ballast on site? And then would they manipulate it with rail mounted diggers or with road going JCB type machines?).

Then how were the actual rails and sleepers be put in place? I think, but I'm not sure, that nowadays the sleepers and rails arrive already assembled, but back then were the sleepers laid down first (manually?) and then the rails added?

 

Outside of your timescale, but they still sometimes manually lay sleepers.

 

One of the lines outside my house was relaid earlier this year.

The (simplified) process was:

 

Unbolt the fishplates and lift the track panels with road/rail "diggers" fitted with grabs onto YKA Ospreys on the adjacent line. The sliding expansion joint that had been fitted at the end of the previous night's work was lifted out and moved about 700 feet up the line to be put into place for the end of this night's possession. The joint had only been held in place with temporary fishplates and C clamps.

The same diggers - now with buckets - shift some of the top spoil ballast into Falcons (on the tail of the same YKA train)

Small amounts of new ballast were added from yet more Falcons.

A Bulldozer fitted with laser levelling gear, then levels the trackbed.

 

The steel sleepers - which were in stacks of five, previously delivered to site a few weeks previously in OCA/OBA's - were lifted into place by the same diggers - now fitted with grabs again. A few minutes before, one of the track workers had come along with a can of spray paint, marking out every five sleepers. Another guy also marks a straight line at the end of where the sleepers would go

 

The sleepers were then lifted manually from the stack and placed approximately. These two guys then move to the next stack. Three more workers follow on - one with an inverted "T" shaped device that was used to space the sleepers exactly, the other two would shuffle them into place.

 

The rails, which had previously been dropped into the adjacent four foot are then slewed across by the same diggers. Various cuts are made at the end of each rail length to make it fit from where they had finished the previous night's work. The rails are then clipped into place and any joints were fixed with temporary clamps - the full joint being Thermite welded about a week later.

More ballast was then added over the top and a tamper then comes along and packs the ballast in/under/around the new track. Sweeper units - fixed to one of the diggers then come along and make it look neat!

 

700 feet relaid in about 6 hours and 45mph ready the morning after. Further tamping/tidying was carried out a couple of weeks later.

 

The other line had been relaid about two years ago using the Balfour Beatty self propelled track relaying train where the sleepers are carried by the train and moved forward with cradles to be laid in front of the advancing train. The rails had been dropped and welded into long lengths a few weeks previously. This train relaid about 1 mile in a one day possession.

 

There's some relaying work going on about 15 miles away overnight and looking at the train formations passing me the morning after, the sleepers are being brought in every night and unloaded to site as required.The first few wagons are Falcons with spoil ballast, then the YQA/FJA, then more falcons, mainly empty, but a couple containing new ballast. I think concrete sleepers are being used as the wagons are YQA Parr and YSA Salmon, with a FJA Tench that is used to carry the waste timber packing that is used between the sleepers.

Steel sleepers can be delivered to site earlier, as they can be stacked easily and lifted manually (albeit one at a time).

 

On other projects the ballast could be brought to site with MRA sidetippers and the final layer of ballast applied with autoballasters.

 

Cheers,

Mick

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In the early 1980's and before most track laying was done in 60' panels.

 

On the first week of work if it was planned to reuse the existing CWR, the CWR would be replaced by 60'-0" plant rails.

If the existing CWR was not to be reused it would be flame cut into 60'-0" lengths on the first relaying week-end.

Plant rails were old 60'-0" rails that were not quite good enough for long time reuse as servicable material.

 

On week two the old track would be lifted out in panels using a TRM (Track Relaying Machine), and loaded onto Salmon wagons.

The old ballast would then be excavated using a bulldozer with a side tipping bucket, and loaded into open spoil wagons. Grampus,

old five plankers, coal 16's, iron ore tipplers, basically anything that was available. New bottom ballast would be unloaded from Mermaid wagons, and levelled using the dozers. If Mermaids were in short supply you might only have three or four for each end of the job. You used these to make a ramp and laid the track through the middle of the job on the bottom of the hole. The new track would then be laid using the TRM again in 60'-0" panels. Once the track was in it would be lifted and packed using hand jacks and shovels, to remove the worst of the twists. The hopper train would then be run through the site and more stone dropped, the track would then be lifted and packed again. This was repeated until the track was at the right line and level, and fully boxed in. Derailments of the four wheeled hoppers were frequent. The solution was to put hand jacks under the axleboxes and jack the wagon up higher than the rails. The wagon would then be pushed off the jacks in the direction of the rails. This was repeated until the wheels landed back on the rails.

During the week following a gang would stay on site lifting and packing as required and generally tidying up the job.

 

This would be repeated until all the old track had been relayed.

 

The final week would involve the site being tamped, to get the line and level just right. Then the plant rails would be replaced with the original or new CWR, which would be destrssed to make sure it did not buckle in hot weather.

 

 

Another option was to ballast clean the track using a PABC and leave it 5" low. It could then be relayed the following week, the combination of the 5" low and the holes left by the removed sleepers giving a bed the required 8" low for the new track to be laid on, once the ballast had been scarrified.

 

 

There is a British Transport Film showing P-Fab relaying, they make a bit of a meal of it compared to how it was done on the LM, but thats what you expect from the Western.

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Things then started to change in the late 1980's and early 1990's.....

 

There were three major changes to the way standard PW renewals were carried out.

 

First the plant used to do the actual digging became more modern, the 1960's style Cat 951 and Drott dozers were seen no more. Being replaced by the new small 360' machines that were becoming available. These allowed more accurate digging and could unload as well as load wagons on site.

 

This reduced our dependence on Mermaid side tipping wagons, a wagon holding 14 tons of ballast. The whole wagon body of which could be tipped by two men turning a large handle known as a spider placed over a spigot on the wagon side. In true railway style a hydraulic machine to power tip these wagons which were basically a pre war GWR design, was introduced for the final few years of this type of wagons fifty or sixty year active life. No more when laying a sand blanket would I have to stand on the thin spots to encourage the men with the shovels to throw the sand in the right place. The sand had always been delivered in Plaice wagons, an evil design of wagon where the door hinges were very weak and prone to breakage. Open a door with broken hinges from the ground and it would drop off the wagon like a guillotine blade. Now sand and ballast could be delivered in normal open wagons and unloaded quickly, and without hordes of men.

 

Then control of the depth of the dig and the leveling of the ballast layers changed from being done relative to an adjacent rail using a spirit level on a timber batten, To the use of a laser beacon that could be adjusted for height and gradient. This was at first used to directly control the cutting depth of dozers and PABC's, and also to give a depth indication in the cab of a 360' excavator via a detector mounted high on the diggers arm. While the first two worked well, the control of the 360' machines while it worked was a faff to set up, and the detector kept getting caught in the overhead knitting. So we soon changed to having the tech staff measuring the depth of the dig with a tool called a rod eye, and making dig deeper, shallower etc gestures to the drivers. Strangely although the laser equipment was all metric the gesturing allways seemed to be done in inches. The great benefit of this system was that the top surface of the ballast could be made very flat, particually after it had been compacted. This flat surface made it possible to clip up rails on to sleepers laid loosely on the ballast with only slight amounts of sleeper moving and lifting being needed.

 

 

Thirdly we changed from doing the relaying in 60'-0" made up panels, to relaying using loose sleepers. These were still placed by a TRM, but were spaced by a 60'-0" long lifting beam with hooks hanging from chains at the required intervals, rather than being attached to temporary rails. This gave several savings in that the sleepers could be delivered to site direct from the manufacturer, so saving the costs of building up new panels at the local PAD. It also removed the need for plant rails as the old sleepers were generally forked out into Pike wagons by small 360' excavators fitted with an inward facing pair of forks instead of a bucket. The job would then be dug the bottom of the hole would be profiled by the laser dozer to give a nice even depth and crossfall. The new bottom stone would then be unloaded, then the laser dozer would again be run through the job, to level the top surface. You could also use it to apply cant and vertical curves to the top surface, so the newly installed track needed less work later. If you were very lucky you could find yourself trying to produce a cant transition, superimposed on a vertical curve. All the adjustments being made manually on a box with a couple of small switches called a wander lead. Due to limits in the length the cables could be, this had to be done while walking backwards over the ploughed field of newly unloaded ballast. While the dozer followed you on the end of a 10' long length of cable. This was hot work in the summer as you were close enough to the dozer that you could feel the air blast from the fan blowing air at you through the machines radiator.

 

Once the ballast had been laid and compacted, the sleepers would be placed to the correct line by the TRM, a paint line or one of the cables from the site lighting would be used to help the men working with the TRM get this right. Once the sleepers were in position the new or saved existing CWR would be put straight onto the rail seatings and clipped up. This could be done with a hydraulic machine known as a rail threader, by a rail thimble which was a set of rollers carried by a large road rail excavator or on smaller jobs in the early days a standard Camlock might be attached to one of the digging excavators. Once the rail was on the sleepers it could be clipped up usually by hand but sometimes various power clippers were tried.

 

Once the rails were on and clipped up the ballast would be unoaded and the rails welded, ready for tamping.

 

This method allowed jobs to be opened at 50MPH compared to the traditional methods 20MPH, and once DTS machines became available to further compact the ballast during the tamping operation linespeed re-opening became possible.

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Thirdly we changed from doing the relaying in 60'-0" made up panels, to relaying using loose sleepers. These were still placed by a TRM, but were spaced by a 60'-0" long lifting beam with hooks hanging from chains at the required intervals, rather than being attached to temporary rails.

 

Pic of a lifting beam.

 

post-408-0-56645500-1342651925.jpg

 

And my take on it.....

 

post-408-0-14531100-1342652069.jpg

 

Cheers,

Mick

p.s I haven't any decent photos of my own relaying observations as it was dark!

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If you want to see a railway (re)built from scratch, look at the Rother Valley Railway website; they're currently building the bit from Robertsbridge towards the existing K&ESR at Junction Road.

 

You can see the formation being build from the ground up, bridges replaced, basic track base, ballast and track laying.

 

 

Sorry I can't remember the link.

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