Progress up to lockdown
On 16th March 2020, our Civil Engineers embarked on probably the biggest civil engineering project in the history of the KWVR during the preservation era.
As we approach the time when work will start again to ‘finish the job’, Chief Civil Engineer, James Barlow, takes up the story, a story he wasn’t expecting to write of a job handed to him when appointed to his new role – From the 16th March to the imposition of lockdown.
Bridge 11 – A Trilogy in Two Parts
James Barlow takes up the story
The lockdown has provided me with sufficient time in which to, metaphorically, put pen to paper on a news article for Bridge 11. Disappointingly this was never meant to be a story told in two parts, but I suppose if I couldn’t take a joke then I shouldn’t have joined! Here is part one.
From 1904 - 2020
Bridge 11 crosses the River Worth to the South of Ingrow Tunnel, close to the new housing that has been built on the site of the old mill. In its current form the Bridge was built in 1904 by the Midland Railway to replace an older wooden trestle structure.
The bridge consists of two spans, one referred to as the wet span and one the dry span. Other than during flood conditions, February 2020 for example, the South span remains dry. Each span was built with four iron girders: two central main girders made of wrought iron and two outer girders made of cast iron. These girders sit on stone abutments and a central pier. A timber deck is laid across the girders, ballast and track then laid on top of that and there is your bridge. The iron girders were second hand when installed in 1904, cascaded down from the main lines where stronger bridges were required for the ever increasingly heavy engines that were being produced.
The timber deck survived until 1974, when, over the winter, KWVR volunteers replaced it with timber joists from a warehouse adjacent to Bradford Forster Square Station, which was being demolished at the time. Fortunate timing on our part as we got the timber quite cheap! At the same time one of the cast iron outer girders was replaced with a timber beam.
The Writing's On The Wall
Recent inspections showed that bridge was starting to deteriorate, particularly the second-hand timber deck, timber beam and also timber edge boards which held the ballast in. At their age, the iron girders owed us nothing and were also viewed to be reaching the end of their useful life. The decision was taken to renew the deck completely with concrete designed to modern standards, particularly including standards for retaining derailed trains. The abutments and piers are in good condition and are suitable for reuse.
Design, Planning & Preparation
From Design to Planning
Design work was undertaken in 2018 and 2019 by Cass Hayward, under the supervision of our former Chief Civil Engineer, Arthur Walker. In November, Arthur retired from regular front line volunteering as the railways Chief Civil Engineer, handing that, and the renewal of Bridge 11, over to me. As soon as we confirmed with the railway’s management the date in March, we started planning fast to ensure we could meet the March possession dates.
In January this year work on the ground began, to prepare for delivery of the new beams. To achieve this we had to construct crane outrigger pads and also reduce the cant (difference in height between rails) from 50mm to 0mm to allow the Bahamas Loco Society (BLS) rail crane to lift the beams. Each of the beams weighs around 17 tons, certainly not light! Plenty of other preparatory works were also undertaken, such as constructing a new tunnel walkway, surveying, clearance of trees and generally tidying the site ready for the big day. My kitchen became an office for the months beforehand, every night I would sit down and go through the planning, produce the documentation, method statements, risk assessments etc. All the requirements of modern legislation and ensuring we protect our volunteers.
29th & 30th January – bridge components moved on site.
The original plan was to take 19 days from Monday 16th March to Friday 3rd April, this would give us three, five day weeks to complete the work, with the middle weekends available as contingency.
The first week would focus on removing the existing track and bridge deck and preparing the stone abutments and pier for the new bridge bearings. Week two was to focus on the installation of the new concrete bridge deck. Finally, week three was for waterproofing the structure and reinstating the track. Simple.
So how did it actually go on site?
Day by Day to COVID-19 Closedown
Monday 16th March
Day one got off to a slow start, they always do. The locomotives left Haworth first thing to come to Ingrow to collect the crane. The class 20 and 37 were the ones to take the crane to site, with Vulcan and our trusty Atlas wagon stationed in Ingrow Yard ready to act as a shuttle for people, tools, materials and equipment between Ingrow Yard and the bridge site. Due to the worksite, the crane had to be taken above the bridge, where it could then offload its north weight relieving bogie and the runner and then be lowered down to its final position for lifting.
Once the crane was in position and secured, we very quickly began removing the track and clearing ballast.
Tuesday 17th March
Day two got off to a much faster start, by 09:00 all the ballast had been cleared off the deck. I then marked the location of the central girders so that the excavator could keep its tracks over them on the timber deck. We then began removing the timber deck.
The excavator placed the deck behind itself and our Taylor Hubbard diesel crane came up from Ingrow Yard and took them away, neatly stacking them at the side of the line out of the way for future collection. Once the South span deck and handrails had been removed, the BLS crane lifted out the four iron girders. Work continued and at the end of the day we had just 1m of deck to remove ready for Wednesday morning.
Wednesday 18th March
The last bits of the timber deck were removed and by lunch the beams had been completely lifted out. At this stage we began clearing the abutments and piers. A site engineer from J. Murphy & Sons, a large contractor, took volunteer leave to help us with setting out the bridge bearing positions and centre line of the new bridge. This is an activity we could not undertake with our own volunteers, we just didn’t have the expertise for this level of accuracy. So a massive thanks to Jack and his company for helping with that. With the existing piers and abutment built to fall with the track, we needed to install some new concrete and grout underneath as the new bearings were to be level in all planes (X,Y,Z), the top level of the bearing is between 45mm and 185mm above the existing abutments and pier. The formwork was installed ready to start concreting on Thursday.
Thursday 19th March to Sunday 22nd March
Almost all activities over these four days focused on the bridge bearings. Concrete was poured on Thursday, and after being protected from the elements was left to cure overnight. Friday was the day to install the bearing steel plates and start grouting. The bearing plates were lifted in by the BLS crane on the South abutment and the Taylor Hubbard crane on the North abutment and pier. The plates were lifted in with adjustable upstands along their length, this allowed the bearing plate to be set at the correct level. A grout was used for the last 20mm to 30mm as it is a more liquid substance and more effectively fills the gaps, flowing beneath the plate, providing a strong foundation.
Grouting continued into Saturday, followed by drilling of the bearing plate anchors to prevent damaging movement. Before the beams are
installed the final layer of the bearing is the Elastomeric Strip. This rubber strip sits on the steel plate and allows the bridge to move slightly during expansion and contraction with temperature and also when trains pass over the structure. Allowing small movements reduces the force in the bridge deck and ensures the bridge remains in use for the longest possible time.
While all this work was going on, outrigger bases for the 100-ton road crane were constructed, the rails between the access gate to the north and the bridge were removed to allow access for the road crane. Debris netting and sheets beneath the bridge for use during demolition were cleared and removed.
Monday 23rd March
First thing, the 100-ton road crane, provided by Emsley Crane Hire, arrived on site and began setting up. By lunch it was ready to go, and just like that the four new concrete beams for the wet span were lifted in. The reinforcement for the stitch joints were lifted ready for installation. For the lifting in of the beams, I was assisted by four of my colleagues from Network Rail. Another massive thank you, this time to Yvonne, Georgios, James and Alasdair for their help on the day. I also had help from Brian at Taziker who provided professional advice and guidance on the installation of the final layer of the bridge bearing. Five of the many people throughout the rail and construction industry and our usual volunteers who have taken volunteer time to help with this job, and to whom I will forever be in debt.
The COVID-19 Factor
Prime Minister, Boris Johnson
At 20:30 Prime Minister, Boris Johnson, made his announcement, and, as volunteers had understandably already begun to isolate, the decision was taken to shut the site down.
Tuesday 24th March
The site was shut down. We quickly moved to clear the site of materials and equipment. The Vintage Carriage Trust (VCT) was shunted to allow us to fit Vulcan and 37 075 in for safe keeping, big thank you to the VCT for that. The BLS crane lifted in the two flat central concrete beams for the South span, not into their final position but to provide a method to get the crane back to site. These beams will allow us to put a temporary 10ft track in place as the crane is lowered back into position. The BLS crane was then collected and taken to Haworth for safe keeping. A difficult day as we all watched over two years of planning come to an unfinished stop.
COVID-19 was continually on my mind as we went through the project. When work started there was no need for us to cancel, it could have potentially led to problems with suppliers and contractors. Although, for the record, all our contractors and suppliers have been fantastic with us. As the week went on, I continually updated advice to volunteers. This was rapidly followed by an instruction that only essential site staff should attend and then followed by a site shut down.
Why Stop Now?
Many have questioned why we stopped when other construction sites were told to continue. The principle reason is that the number of volunteers who were classed as vulnerable, had to prioritise their role as key workers or simply viewed volunteering as a non-essential activity and quite rightly followed government advice to stay at home. Most of all, we wanted to protect our volunteers, and with the railway closed indefinitely, there was no good reason for us to continue. We could no longer safely run the site and therefore we had to shut down. A tough decision but the right one.
And that brings us to today. I hope you found this interesting, any questions direct them to the railway and they will their way to me.
Last of all, I hope you have all kept safe and well during these challenging times.
Watch this space
The Railway waketh! Keep your eyes peeled for James’ report on Part 2 – sometime in August!