Saturday, 31 October 2015

And down they go again

What a fantastic day today! Blazing sunshine, good progress, plenty of cameraderie, and cake. There was a well drilled gang of 12 of us today, to see how far we could get with the 400 concrete sleepers loaded on Thursday.
This is the situation at the beginning of the day, with the railhead at the start of the curve to Little Buckland. The two Warflats with the sleepers had been positioned just behind the camera, and 4 sleepers are being lifted into position at the foot crossing, so that rails might be laid over them and the crossing finished off to a basic level.

Then Alan in the telehandler started on the long job of transporting the sleepers in batches of 4 or 8 (and annoyingly, sometimes in odd numbers, which throws out the placement jig we use - must try harder, Alan).

It required a lot of skill to remove the top layer, as visibility of what the forks are doing is pretty minimal on the highest layer. Alan did well however, and soon had us buzzing down at the working end.

It felt like quite a milepost to start on the curve, after the long Laverton straight. At the other end of the curve, behind the camera here, is Little Buckland bridge and the target of the first track relaying phase. Here, it is still out of sight to the team.

Riders galloping across the fields in the distance
Then there was a commotion in the distance, as the North Cotswold Hunt galloped past across the field in the background. They vanished behind a spinney, whereupon a fox ran out and hid in the ditch that leads away from the recently rebuilt culvert. We could only stand and stare. A deer ran out the other way, and then a red helicopter came in to land, followed by two first responder cars.

After a pause, the hunt resumed. Two quad bikes raced along the hedge up to the railway embankment, and without slowing down turned sharp right along the railway, so much so, that one went along on two wheels. Our jaws slackened...

One quad bike then stopped to release a huge bird of prey. The wing span was as wide as its handler was tall, it seemed to us that this must be an eagle, as it was much bigger than a falcon.

The bird was released and flew off after the fox, which it duly found and despatched.

The dogs ran up as did a rider in hunting pink, but seemingly after the event, the bird had got there first.

By this time all relaying work had ceased, as we watched the events unroll before us.

To your blogger, there was a certain sense of pride and history - this is the countryside, and these are our neighbours. It is a centuries old tradition, and we were somewhat priveleged to have a grandstand seat to watch it all.

We resumed our own activities, that of laying track, but it seemed rather more banal after such excitement.

Thanks to the excellent weather and good turnout of experienced volunteers, we were well into the curve by lunch time, with the rearmost tree on the left representing the 150 sleeper mark. Here Alan is bringing another set of eight, which Steve in the JCB lifts on to the trackbed in groups of four using the two white spacers.

There was some hilarity as Steve felt the need to air his stockinged foot outside the cab, with much coughing and holding of noses amongst the gang.

In fact poor Steve had sprained it a few days earlier, and we can be grateful that he came nonetheless to play this key role in the JCB during our sleeper laying day.

More hilarity ensued when Jim came up to 'give him a hand', which Steve turned down as he hadn't asked for a whole arm. (shades of Hancock's 'Blood Donor' here)

Finding no takers for his arm in the JCB, Jim stuck it on a pin to point us the way to Broadway.

Very useful, thank you Jim ! No 'arm in that, we suppose (and believe me, many more puns followed in that genre all afternoon)

Finally, and with no mid morning break for coffee, lunchtime arrived and was most welcome. A slice of Mrs. B's most excellent sponge cake beckoned.

Seen from the top of the flats carrying rail, here is how far we had reached by lunch time. The JCB marks the limit of the sleeper laying at this point, almost out of sight. The haystack is where the quad bikes skidded round the corner on two wheels.

As the sun began to go down, we realised that, incredibly, we were going to be able to lay every one of the 400 sleepers loaded on Thursday, thus enabling the train to be returned to load some more. This made good logistical sense. It seems that laying 400 sleepers in a single day is quite a record, certainly in recent memory, beaten only once in a relay where all the sleepers were already on site, and did not have to be ferried in by telehandler from a train.

In this picture, the last load is just arriving. The mid point of the excercise today was a little this side of the trackside tree on the right, in the background. How far away it now seems.

This is the end of the sleeper laying today. We didn't lay any rail, as emptying the two Warflats was our priority. The rail can be lifted in by a smaller team on the next available day. There is also some talk of further ballast spreading, from Little Buckland to bridge 4 at Peasebrook farm, so time will tell what gets done first, it all seems equally important.

Looking the other way from the same spot - and with the golden sun behind the camera - we can see that the sleeper laying is now well within sight of Little Buckland bridge, situated between the two poles.

The last picture of the day is from the top of the flats again - compare with the opening shot - and shows the sleepers disappearing into the distance, and the gang packing up in the foreground.

This was a most successful day, and we left for home with a great feeling of satisfaction and much achieved.

Thursday, 29 October 2015

Sleepers awake

Part of building the extension is finding yourself a good supply of concrete sleepers. We have such a good supply! With some foresight years ago, a large stash was acquired which was put into storage at Gotherington, in a small triangle of railway owned land known colloquially as 'Skew Bridge'.

These two pictures give you an idea of what's at the site. It's a mixture of SHC (hoop) type and Pandrol type sleepers. In this picture, looking south, you can see a nice line of stacks with bearers in between - this is what a party of us came to load today.

The nice line of stacks took several days to achieve, as they have been picked out of the jumble in the picture below. The word 'mixture' gives you a clue. On delivery some years ago now they were unloaded under time pressure with potential demurrage charges payable, so they are not so
arranged today as to make for easy loading. In addition, trees had grown in between which needed cutting down and burning. The site is now clear, and the first stacks ready for the train.

The pile of lighter coloured sleepers are the rejects, discarded due to bent hoops or damaged concrete. Luckily the ratio is fairly low.

Today was a non - running day, so a PWay train went out, firstly to unload a corrugated lamp hut at CRC, and then on the return journey to pause at Skew Bridge for loading with as many sleepers as we could muster.

Here the Class 73 ED has arrived from Cheltenham with two Warflats, ready for loading and later taking up to the extension headshunt at Laverton.

This is where our new(-ish) telehandler really comes into its own, and with an experienced driver at the controls the job of moving the heavy concrete sleepers is made so much easier. A concrete sleeper weighs between 300 - 400Kg, so is impossible to lift by human hand, although they can be manoeuvered around using bars.

 There was a group of 5 of us today, just the right number to act as banksmen, site supervisor and telehandler driver. The sleepers are put in stacks separated by bearers, which protect the hoops, and make unloading at the extension end easier too.

On completion, the stacks are secured down tight with straps.

The day began with a site crowded with sleeper stacks, but as the day progressed, there was more and more room and this will make the task of sorting out further supplies somewhat easier than in the past.

This view from the signal post gives you a good idea of the size of this small site, and the volume of sleepers that we have secured for the extension to Broadway. Plenty more to go after this train !

The first Warflat is full, now on to the second.
The weather was a bit miserable. A rainy start was forecast - correct - but it was meant to clear up at lunchtime - not correct. The steady drizzle actually increased to a point where we thought, this is a good time to break for lunch, which was held in the not-actually-very-roomy 'Queen Mary' bogie brake van. The 'roomy' bit seems to refer to the balconies, the interior being the same size as a normal non-bogie brake. But it was cosy; pity we didn't have time to light the fire.

After lunch we loaded the remaining stacks that were ready. With some space still available on the second Warflat, we made up further stacks, extracting the sleepers from a  pile that disappeared into the undergrowth. On presentation upon the two bearers on the ground, the sleepers need to be barred into the correct position, and then checked for suitability. That's a bit slower than simply loading the from the ready stacks, but in the end what brought work to a halt was the exhaustion of our supply of wooden bearers.

Here's the product of our efforts today - just over 400 sleepers loaded up, and a train ready to go. We were pretty happy with this.

The 400 sleepers represent 15 lengths @ 26 sleepers each, or a potential extension length of 270m. It should take us a good way round the bend towards Little Buckland bridge, the target of our first relaying phase.

After a quick phone call, the ED came down from Winchcombe again to pick up the loaded train. Here it is setting off for Laverton again.

This little supply of sleepers will give the relaying gang something to do... probably two days' worth, the first of which will take place almost immediately, i.e. this Saturday.

Stay tuned, and see how far they got !

Monday, 26 October 2015

Quick update

A start has been made on spreading more ballast beyond Little Buckland bridge. A large supply was stocked here earlier, and in order to let vehicles through - such as one in support of the drainage gang - the piles were narrowed to free up the down line. The surplus ballast was used to make a start on the next bit towards Peasebrook farm. In the far distance you can just about make out Broadway goods shed. Setting out posts have also been planted on the left, ready for the next ballast spreading in the near future.

Looking north towards Broadway
Looking south, towards bridge 5, Little Buckland.
Here is the remainder of the ballast pile, and Little Buckland bridge visible in the near distance. The rail head is currently on the other end of the bend that you can see. We hope to be able to post a further update on Thursday, after a day of sleeper loading, in readiness for the next spurt of track laying.

Finally, a picture of the drainage and fencing that has been going on relentlessly. A very neat job it is too. Ballast piles are on the left, looking towards Broadway and Peasebrook Farm.

Wednesday, 7 October 2015

Thermite welding at Laverton - a special report

A four unit team from Haigh Rail Ltd came today in 4 vans to weld up the first ten pairs of rails towards Broadway. Each team busied itself with a separate set of the 18 joints in question.

This exothermic welding process was rather spectacular, and you will excuse the larger number of pictures in this posting, which will describe how it was done. Your blogger, although well acquainted with Pway work, had never seen this, and no doubt many of our readers will find it interesting as well.

On a cold and blustery day, the 4 vans lined up along the rail head. Each van held the materials and gas bottles that support a crew to make a weld.

Pending the welding, the rails were not permanently fixed to the sleepers, being clipped only on every other sleeper, and without pads. Now that the welds have been effected, we can properly clip up this stretch.

The first step is to create a gap between the rails to be joined that is exactly the right size. This gap is made with a special cutting torch that slices off the end of the rail of the desired thickness.

With the proper gap, the rails are then checked for a perfect alignment, and corrected where necessary with wedges, and sometimes, with brute force.

Using a special frame clamped to the rail, a pair of moulds is attached around the joint to be welded.

The joints around these moulds are then sealed using a special sand with a resin in it, which makes it sticky so that it can be tamped into place.

The joint is then heated using a special gas burner which blasts a flame into the mould, and which erupts back out on the top, with a rather spectacular effect of a V Twin flame that roars out. A bit like my motorbike then.

Mick explains how the heat can be adjusted to the right degree.

A single use crucible containing the Aluminium and iron oxide powder is then place on top of the mould, and ignited with a special taper.

To the left and right of the moulds are pots which catch the molten Aluminium which is released as part of the process. This is lighter than the iron which sinks to the bottom and into the joint, so the Aluminium floats to the top and can be collected at the sides.

Shortly after the reaction starts, the plug at the bottom of the crucible melts, the iron flows into the joint below, and the aluminium into the sides, with a roar of flames and heat.

It doesn't take long for the reaction to conclude, after which you simply lift off the single use crucible, leaving two pots of molten Aluminium at the sides.

These pots are then upturned into the empty crucible for disposal.

Once the apparatus has been removed, the remains of the moulds are left, as well as a stub, which is too big to be ground off. With the use of this hydraulic cutter, the stub is then cut off.

The cutter just needs a lot of pumping, to force its jaws together through the stub, which is still hot.

This is the stub that is left at the end of the thermite welding process.

A portable motorised rail grinder is then used to grind off the remains of the stub, and to achieve a completely flat rail surface.

This picture shows the untreated stub in the foreground, and rail grinding in progress at the rear.

Finally the inside of the web is cleaned up using a Hilti with a needle gun attachment.

Surprisingly, there were different forms of crucible in use. Each supplier of the materials has his own, slightly different system. The next couple of images show you the types used by one of the other teams, just as curious as the first.

A few joints away, a second team is seen setting up their pair of rails, which were not where they should be. Although great care was taken to spread the ballast out evenly using a laser level on the JCB, it can still happen that there is a height difference between rails to be welded, such as is the case on the right. Rails with concrete sleepers are notoriously heavy, so you can see the effort that was needed to shift them, even if only a few millimeters.

This team was using a French single use crucible, which had to be filled with the powder kept in special tubs. This is what it looks like, the silver colour being accounted for by the Aluminium.

The process generates heat up to 3000 degrees C, which is considerable. According to a recent television documentary, it is thought that the extreme heat of the molten Aluminium from the 9/11 planes burning accounted for the unexpected weakening of the metal framework inside the towers, not simply the crash.

This French system has trays facing the other way, and we can see here how the powder is about to be lit from one of the pre-heating torches. A lid goes on top.

Mick supervises the process, and gives advice based on the many years he's been doing this.

The lid goes on. In the foreground is a tube of sealant, which is used in this process instead of the resinous sand used in the first.

The burn takes place, and after a short while the aluminium starts to flow into the two receptacles on either side. You can imagine the heat, even from several feet away.

In fact, there is so much heat released that it lingers, and frozen GWSR volunteers can avail themselves of it and warm their hands.

A cup of coffee and a chat in Andy's car was also a rather reviving pleasure, out of the wind on top of this exposed embankment.

The rail grinder then came along here as well, and showed us how it can do sides as well as the top. A neatly designed machine.

Then, finally, a third type of crucible was in use at the Laverton end. This is the classic type of crucible, which is multi use (ie not throwaway.)

This steel crucible is mounted on a frame, which allows it to be swung into place once it is loaded, and the moulds have been attached.

Here is a view into the top of the mould. The gas burner blows flames into the centre opening, and the flames, once round the joint, come out again through the two holes on the side, so making the 'Vee' effect.

The pots collect the molten Aluminium.

Here a special plug is inserted into the bottom of the multi use crucible. This melts at a predetermined temperature, and allows the molten iron at the bottom to flow into the joint.

The Aluminium and iron oxide powder is then poured into the top, and the whole thing lit with the taper.

As this takes place, the gas burner is heating the up the joint (flames at the front), and when it is at the right temperature, gauged through the use of stop watches, the crucible is swung over the mould and ignited.

There isn't a picture of this one going off, but there are two videos.

The first, longer one, shows the burn using the single use metal container, as well as the removal of the stub with the hydraulic jaws:

The second film, rather shorter, shows the multi use crucible ignited, which seemed a bit more spectacular still:

Finally, a quick check at the Broadway goods shed showed that the 45T excavator had finished the job for which it was hired. Our engineer and our contractors now have a good understanding of the structure of the embankment there, and we await their options and recommendations.

The 15 trenches were back filled today, and the slope of the embankment regraded to give a gentler slope, starting at the row of yellow tipped posts. Unfortunately, this will no longer give room for the siding that was there, but there will be the double track main line, on the right. The photograph was taken from the position of the former siding.