The Selby Diversion – a talk by Hugh Fenwick, Resident Engineer for the Selby Diversion

2023 is the 40th anniversary of the opening of the Selby Diversion railway, now part of the present East Coast Main Line between York and Doncaster

•The first public train ran over the new railway on  Friday 30th September 1983 and the railway opened fully to traffic on Monday 3rd  October 1983.

•This presentation looks at why the railway was built, how it was developed and shows in some detail how it was built.

•Most of the images and drawings are from that time.

The story starts during the fuel crisis of the early 1970s. The NCB’s 1973 corporate “Plan for Coal” included a new Selby Coalfield to increase coal production.

The mine would undermine the ECML, mining subsidence would affect the water table and could trigger unpredictable movement that would result in four to six TSR’s being applied at any one time on the ECML between York and Selby.

The extent of the mine and the position of the original ECML are indicated on this plan.

Difficult ground conditions would cause unpredictable subsidence affecting the East Coast Main Line track and structures. Speed limits would be essential and British Rail Board costs would be considerable.

At the time, BR was building the HST train sets and starting the work needed to improve the ECML track alignment for the introduction of the full Inter-City 125 HST timetable in May 1979.

As an aside, on 12 June 1973 the prototype InterCity 125 (power cars 43000 and 43001) set the world speed record for diesel traction at 143.2 mph (230.5 km/h) and on 1 November 1987 an HST set the world record for the fastest diesel-powered train, a speed of 148 mph (238 km/h), which still stands.

Speed restrictions due to the mining subsidence would destroy the benefits of the Inter-City 125 investment.

In early discussions with the National Coal Board, BRB advised that if the coal was worked the ECML could not be used between Selby and York for Inter-City 125 services and the line would require diverting.

Statutory agreements between BR and the NCB allowed two approaches to addressing mining subsidence. BR could either purchase the coal beneath the railway and leaving it in place to support the line or accept the subsidence, in which case the NCB would pay the major part of costs caused by settlement of the railway.

Purchasing support would affect the way the NCB planned to extract the coal from the Selby Mine, reducing output from 10 million tonnes per annum to 7million. That was unacceptable to the NCB.

•Having the railway supported on coal would also create land drainage problems that might prove insuperable in guaranteeing the drainage of the Ouse river valley.

The NCB accepted speed restrictions would be necessary, BRB’s costs could be considerable, the ECML could not be used between Selby and York for Inter-City 125 services and the line would require diverting.

•Consequently, the NCB planned the Selby Coalfield on the basis that the ECML would be diverted.

Six route options were considered. Clearly the Colton Extension, coloured red on this drawing, best satisfied the route requirements.

•Although it was approximately half a mile (800metres) longer than the original line through Selby, it delivered a 2-minute journey time reduction due to the avoidance of permanent speed restrictions on the original route at Selby round the curves and over the swing bridge.

To avoid existing and proposed mineral workings as far as possible it was fitted between the Selby Mine and a planned gypsum area to the west.

•The gypsum mine planning area forced the Colton Extension eastwards into Bishop Wood, an environmentally sensitive area. Apart from this, the environment impact of the low-level railway avoiding built up areas was low.

Only six properties were within 100metres of the railway.

•There was no permanent impact on RAF Church Fenton. However, during construction conditions were imposed on working methods.

•The selected route is 23.5km long (14 miles), double track throughout, designed for 200kmph (125mph) but with curve radii suitable for 250kmph (155mph).

Colton Junction at the north end was the first 200kmph junction in Britain, to provide 200kmph running on the new ECML through the junction with the Sheffield Lines at the north end.

The Leeds-Selby line was moved northwards to enable its new alignment to be built with the original line continuing in use.

The principal features of the new route, working from north to south, are illustrated in this drawing.

•200kmph Colton Junction

•26-span River Wharfe Viaduct

•Bishop Wood

•8-span Selby Dam Viaduct

•Leeds-Selby-Hull Line


•3-span Selby Canal Bridge


•River Aire

•Temple Hirst Junction

·Before the Selby Bill was lodged with Parliament BR consulted North Yorks County Council, Selby District Council and other statutory bodies about the proposed diversion and carried out a public consultation exercise using a caravan travelling to villages near the route.

·In November 1977, the Selby Bill was deposited with Parliament.

·After passage through the House of Commons and House of Lords the Bill received Royal Assent on 26th July 1979, authorising construction of the Colton Extension, now known as the Selby Diversion.

·Soon after in August 1979, tenders were invited for a Preliminary Works Contract to build a road to a new railhead at Hambleton to transport bulk materials – ballast and sleepers – to site

·Tenders were invited also for the Main Civil Engineering Contract to build the Diversion.

·In September 1979 enabling works commenced, comprising long lead-time Utility Diversions, to allow the main construction contract to proceed unhindered.   

· It had taken only 5 years from concept to starting work!

  • First use of Computer Aided Design CAD (MOSS) in UK for railway route and earthworks design
  • Computerised Survey Plotting and Electronic Data Collection by British Rail (Note: GPS not available in 1970s)
  • First 200 kph junction in the UK

All design work for the Diversion was carried out by BR Eastern Region’s in-house design teams here in York.They surveyed the route using aerial surveying linked to detailed field surveys at all road sites and interactions between the existing and new railways. The field work was carried out using an ‘Electronic Total Station’, the first to be used for a British railway survey. It comprised a combined distance measurer and electronic theodolite. This enabled electronic collection of survey data and input to a computer for automated survey drawing. Now, the survey would be done using GPS techniques, which did not exist at the time.

The Diversion was the first British railway to be designed using CAD. Software (MOSS, Modelling Systems) had been developed by a consortium of UK local authority highways engineers for computer aided design of new road schemes. The consortium included highways engineers at Durham County Council. With their help the BR design team designed the route, earthworks and highways alterations using MOSS, which then became the industry standard for railway design.

The Diversion included the first 125mph (200kmph) junction in the UK. Colton Junction was designed for the junction between the new lines and the York to Sheffield lines at the north end of the Diversion.

High Pressure Gas Main Strengthening near Ryther

The Selby Act gave BR powers to compulsory purchase land for the railway. Approx. 600 acres were acquired, about half of which were returned to agricultural use on completion of the project.

The overall cost of the project at 1981 prices was £60m (approx. £300m at 2023 prices). Land acquisition amounted to £3.3m, £37.3.m was for the civil engineering contracts, £11.1m for track installed by BR’s own workforce and £8.3m for signalling.

The Selby Act also provided access to land, allowing the first physical works to commence, alterations to utility services. These were time-critical to achieve the planned completion date of the May 1984 passenger timetable ahead of the mine workings that would affect the original line.

Outages were needed to strengthen high pressure gas mains. They werecrossed by the railway, and to alter high voltage power lines, under which the railway passes, required months or even years notice. Provisional outages had been booked in advance of the Selby Bill being authorised.

The most urgent task following Royal Assent was for the outages to be confirmed and the alterations carried out ahead of the main construction contract.

Work on strengthening this 915mm dia. high pressure gas main near Ryther commenced in  September 1979, only a few weeks after Royal Assent.

Raising 132kV Power line and moving pylons for the Leeds Selby Line

This 132kV powerline at Hambleton, a 400kV power line at Temple Hirst and two large diameter water mains were also altered in 1979 to accommodate construction of the railway.•

•During the project 25 power lines, 20 water mains, 18 telephone lines, 3 gas mains, 3 pumped sewers were altered, plus a large volume of land drainage alterations.

The Preliminary works contract was let in October 1979, to Clugston Construction Ltd, to build a railhead at Hambleton for delivery of materials by rail, stockpiling of ballast, sleepers and other construction materials.

•BR laid the track and installed the associated signalling, commissioned in June 1980.

The contract included construction of a temporary level crossing across the Leeds-Selby lines on the alignment of the new ECML to allow the main contract site traffic to cross those lines.

It also included construction of an access road from the A63 near Hambleton into land to be used for the main contract site offices, workshops, laboratories and other site facilities, adjacent to the Leeds-Selby line.

The preliminary contract was complete in March 1980.

Within days of completion of the preliminary contract the main civil engineering contract was let to A Monk & Co.

They began establishing the site facilities on 21 April 1980.

The first task in building the railway was to stake out the route on the ground

·An important task at the start of the project was to establish an all-weather haul road through the full length of the railway before the onset of winter to achieve the BR objective to run trains at 125mph over the Diversion from the start of the May 1984 passenger timetable.

·Access to site on local roads was severely restricted by NYCC. Access to the alignment was permitted on only 5 roads and tonnage limits were set on what could be brought to site on all but one of these.

·The only road with unlimited tonnage access was the A19.

·To deliver the challenging construction programme it was essential to have access to all work sites, particularly to bridges.

·Immediately after setting out sections of route, lineside ditches were cut to intercept and maintain land drainage.

·Temporary fences were erected to secure the site.

On 29th July 1980 nearly two hundred people attended a “Creating a Diversion” event at Hambleton close to the site of the new main line.

•The ceremony to commemorate building the railway was hosted by British Rail’s Eastern Region General Manager, Frank Paterson (our President of the FNRM), and was themed on the railway, coal and electricity generating industries working together.

•The Chairmen of the three industries BR, NCB, CEGB plus the Chairman of A Monk & Company Limited, the main contractor building the railway, and the General Manager signed a commemorative scroll for the occasion.

•The scroll was placed and secured in a stainless-steel casket along with a copy of the Act of Parliament authorising construction of the railway, and several contemporary artefacts.

•The casket was ceremoniously buried in a chamber cast in the base of a commemorative stone.

•Here, the four chairmen wait for Frank Paterson to wave the green flag and give the all-clear to pull the stone into position, while BR Eastern Region’s Chief Civil Engineer, Brian Davis looks on, a little bemused.

Meanwhile, work continued apace on building the haul road.

Bailey Bridges were installed where the route crossed major waterways, the River Aire, Selby Canal, Selby Dam and River Wharfe.

•These were assembled on one side of the waterway with an extended nose section that enabled them to be launched forward over the water.

At lesser watercourses, steel culverts were installed.

•Generally, the base of the embankment was used as the haul road.

•The construction sequence was to cut the crops, compact the ground with heavy rollers, lay  a strong geotextile, then tip rock fill onto this to form the embankment.

Unusually, the topsoil was not stripped as the subsoil was no stronger than the topsoil and the ground was level.

•The geotextile provided some strength and prevented silt and clay ingress into the haul road rock.

Rock fill was specified for the railway embankments because much of the route was subject to flooding. The rock fill allows flood water to rise and fall without affecting embankment stability and avoids having to restrict train speeds on the operational railway.

Two 300mm thick layers of rock fill were placed and compacted on the geotextile to create the haul road.

•Where the haul road crossed public roads, these were strengthened with concrete slabs at the road crossings and traffic lights were installed.

•The haul road was taken around cuttings to minimise delay to the haul road construction and avoid creating ruts in the railway formation within the cuttings.

By 15th November 1980, a continuous haul road was established from Colton Lane to Temple Hirst Junction.

•This is the 1980 project Christmas card produced by Clifford Elliott, the BR site QS. •Cliffy produced a card each Christmas until completion of the railway, providing a light-hearted and seasonal summary of progress.

•In this “as-built” construction programme the haul road is shown by the red lines. It gave access to enable work to go ahead on all fronts, building the road embankments (yellow lines), bridges (black), road diversions (green), followed by completion of the railway earthworks and ballast laying. Tracklaying was done by BR’s Leeds District Engineer.

•Although the route was over flat rural terrain, construction was not straightforward. Most of the route crossed very weak ground that required special engineering solutions.

It can be seen from the blue line at the bottom of the programme, the timescale for the short section of embankment at the extreme south end of the route, took from November 1980 to June 1982. This was due to the very weak ground conditions.

•So poor were they that part of the embankment north of the river, between the River Aire bridge and Temple Hirst Road, had to be rebuilt in early 1983 to ensure its suitability for running trains at 125mph for the May 1984 passenger timetable.

•There were several challenges in building the embankment at Temple Hirst.

•It was the highest embankment on the Diversion (5.5m. high).

•The underlying ground was the weakest with a predicted embankment settlement of 1.4metres.

•The new embankment was built against the original ECML embankment which  had a factor of safety against failure that would not tolerate reduction.

Temporary speed restrictions on the adjacent ECML during construction work were to be avoided as far as possible.

•A very detailed method of construction of this section of earthworks was specified to ensure the stability of the existing and new embankments.

The first operation was to strip off loose material from the old embankment in 10m. wide panels and replace it with rock fill at a flatter slope to improve stability.

Ground instrumentation was installed in the ground beneath which the new embankment was to be built, to monitor ground settlement, lateral ground movement and water pressure in the ground.

The new embankment was then raised in 900mm stages (4x 225mm layers) with a pause between each stage to check the factor of safety against failure and if needed, allow ground water pressures to dissipate before continuing building.

The existing ECML track geometry was monitored during the embankment work to ensure it continued to be safe to run trains at line speed.

After improving the factor of safety for the existing embankment, a 600mm thick rock fill working platform was placed at the base of the embankment, to provide a working platform on which construction equipment could operate.

Vertical drains were sunk through the rock fill, deep into the ground to accelerate the dissipation of porewater pressure and reduce the time for the embankment to consolidate.

The groundwater pressure was monitored regularly to maintain the embankment stability during construction.

The mass of data from the other instruments was collected by a team of instrument readers using electronic data loggers that could be plugged into a computer terminal equipped with software that processed the stability calculations to provide speedy information for decision making.

•The embankments south of the river were built without incident and without the need to impose speed restrictions on the existing ECML.

•However, problems were encountered north of the River Aire bridge. These will be outlined when describing the River Aire bridge construction.

Moving on to bridges, ground conditions determine the design of bridge foundations.

The route crosses 4 distinct geological areas.

•At the south end (LH end of this section) the ground comprises weak silts and clays, pockets of peat, then sand and gravel overlying the bedrock of Bunter sandstone, 17 metres below ground.

Between Selby Canal and the A63, the Bunter sand and sandstone outcrops.

North of the outcrop, the bedrock dips steeply and is overlain with silts, clays, sand and gravel up to 20metres thick.

•The section at the northern end coloured blue is the Escrick Moraine, which comprises gravelly boulder clay, sands and gravels, stronger than the silty clays to the south, but with an intermediate layer of the sand, weak silts and clays over the bedrock.

All bridges except those at the outcrop required foundations piled down to bedrock

Because the boulder clay is stronger than the silty clays, it needed special measures to reduce the settlement times for the road approach embankments

•As you would expect, the best brains were employed on bridge construction.

•They studied the problems doggedly.

35 bridge structures were built for the Diversion.

Ten were to the design illustrated for roads over the railway.

•A description of their construction sequence follows

The first task was to build the embankments, as the ends of the bridge are supported on bank seats on the embankments,.

At the north end of the site, the relatively stiff clay of the Escrick Moraine would settle slowly and would extend the contract programme.

These embankments were built to a greater height than the finished design, to add weight and accelerate settlement.

Settlement gauges were installed beneath the embankments to monitor the amount and rate of settlement.

The boulder clay was used to build road approach embankments at the north end of the Diversion. It was excavated from two borrow pits, one of which had been used to build the York to Leeds line in the 19th century, at Colton and used for road embankments between Colton and Moor Lane near Ryther

South of Moor Lane, road embankments were built using Bunter sand from a borrow pit between Selby Canal and the A63.

At the Bishopdyke Road  bridge, initially excavated material from the Selby mine shafts was used but it was inconsistent and abandoned in favour of the Bunter sand.

For the piled bridges, the specification required the remaining settlement of the adjacent road embankment to be no more than 75mm before piling could commence, to limit the transfer of load from the embankment onto the piles.

At that stage, a test pile was installed and loaded to 1.5 times its working load.

If the pile passed the load test, production piles could be ordered and installed.

Piers were built in two stages.

•A concrete pile cap was cast over the piles to tie them together and form the base onto which the piers above ground could be built.

•The reinforced concrete piers were then cast in two lifts as shown in these photographs.

The specification required remaining settlement of the embankment to be no more than 50mm before bank seat construction could be carried out.

Here the piers and bank seats, cast on the approach embankments, are complete

The bridge decks comprise precast prestressed concrete inverted T-beams.

•After erection of the beams, the space between them was infilled with concrete to create a solid deck.

•Precast concrete parapets were then craned into position after the remaining settlement of the approach embankment was predicted to be no more than 25mm.

Finally, when 90% of the predicted remaining settlement of the earthworks had occurred, the approach road could be built to North Yorkshire County Council’s specification.

The bridge vertical clearances were designed to allow for future electrification of the line.

Six of these bridges were completed in 1981.

•This is how the 1981 Christmas card reported progress.

The worst flooding ever recorded in the area happened during the contract.

•This is the River Wharfe viaduct in early 1982.

•Here BR Works Inspector, Charlie Heywood, is going to his site office.

•He reached it travelling by bus, train, Land Rover and boat, regardless of flood and traffic lights

•Flooding was not going to stop him from getting to site.

The winter of 1981/82 was also one of the coldest.

•The flood water froze over the ditches. When it subsided, the ice collapsed into them.

•Returning now to construction, a standard design was developed for the three railway viaducts: River Wharfe (26 spans), Selby Dam (8 spans) and Selby Canal (3 spans).

•The viaduct foundations are two large diameter reinforced concrete bored piles, extended above ground as circular columns.

A crosshead across the top of the columns supports the rail deck comprising six box beams, with walkway beams on upstands at each end of the crosshead.

Due to the very poor ground at the river crossings, it was necessary to install steel casings through the upper layers of weak ground to support the sides of the pile bores.

Below the steel casings the bore was filled with bentonite slurry to provide pressure to support to the sides of the bore.

These images show the augur for boring the shafts and the tanks of bentonite

Then the reinforcement cages were constructed

The piles were then concreted from bottom upwards, through a pipe lowered to the base of the pile and progressively raised as concrete filled the bore and displaced the bentonite.

•Here, a mobile concrete pump is charging the tube with concrete.

After completion of the piles, the tops were trimmed to below ground forming a surface for the columns to be cast above ground.

•These were cast within special aluminium formwork to produce a high-quality finish.

The crossheads were cast across the columns and bearings fixed to support the deck beams and allow for expansion and contraction.

A 400 tonnes capacity crane was used to lift the main deck beams onto the bearings.

•At the time, this was one of the largest cranes in the country.

RAF Church Fenton had to be informed of the use of these tall cranes and lights visible to pilots were located at the jib ends.

•Erecting the beams.

The six deck beams were transversally stressed together using Macalloy bars and the upstands for the walkway beams were cast on the crosshead ends.

•The walkway beams were erected using crawler cranes working in tandem on the bridge deck.

Timber mats were placed on the deck to protect it from damage from the crane tracks.

•The decks were later waterproofed using an acrylic membrane sprayed over the deck surface and up the sides of the deck edge beams.

This membrane was then covered with glass reinforced concrete panels to protect it from being damaged by the track ballast.

This is the completed 26-span River Wharfe Viaduct.

The Leeds-Selby intersection bridge that spans the Diversion and the bridge over the River Aire are steel girder bridges.

•The new Leeds-Selby alignment was built to the north of the original alignment to minimise disruption to train services on the Leeds-Selby line during construction of the new bridge and approach embankments.

•The realigned Leeds-Selby line opened to rail traffic on 22nd November 1981.

•The temporary level crossing over the Leeds-Selby was then removed, improving construction traffic flows along the Diversion.

Both bridges are on weak ground. They required abutments to have piled foundations driven to bedrock along with special measures to avoid a step in the track vertical alignment due to the embankments settling behind the piled abutments.

At the River Aire, 1.4 metres settlement was predicted. As the abutments are supported on the bedrock they will not settle. A solution was needed to provide a smooth vertical alignment that would ensure the line could operate at 200kmph (125 mph) for the May 1984 passenger timetable.

The ground was too weak to surcharge the embankment as had been done at some road bridge sites on stronger ground at the north end of the Diversion.

A system of piling was installed to support the embankments adjacent to the bridge abutments.

This Bridge Approach Support Pile system was installed at both the River Aire and the Leeds-Selby Intersection Bridges to address settlement behind the abutments.

Immediately behind the abutment, a grid of piles is driven to bedrock to support the embankment over the grid area and avoid transfer of lateral loading onto the piles supporting the abutment.

Further away from the abutment, piles under the embankment were stopped clear of the bedrock to allow them to settle. As the distance of the piles from the abutment increased, the spacing between piles was also increased, progressively increasing the load per pile and settlement of the embankment to obtain the desired vertical alignment.

This photograph at the intersection bridge shows the abutment piles trimmed and capped ready for building the abutment above ground.

Behind the abutment, the BASP bridge protection steel H-piles are awaiting trimming and the casting of reinforced concrete pile caps over which, the embankment was built.

Here at the River Aire bridge, piles are capped with circular concrete pile heads.

Building the bridge itself at the River Aire was an interesting process.

•The river pier was built within a cofferdam in the river.

As the bridge was close to the existing ECML the steel girders for the spans were brought to site by rail and moved across to the adjacent new embankment, on skates, where they were assembled to form the bridge structure.

The river spans were then launched over the water.

•The cofferdam in the river was created using steel sheet piles driven to bedrock.

•The riverbed and ground beneath it were excavated inside the cofferdam using a grab illustrated here.

• Any loose material in the base was pumped out

To ensure the pier would be founded on solid bedrock divers inspected the excavation base before concreting the base.

•A massive concrete plug was then pumped into place in a single continuous 14-hour concrete pour to seal the bottom of the cofferdam and form the pier foundation.

•The cofferdam was pumped dry, after which the pier was shuttered and cast inside it.

•A view of the pier inside the cofferdam.

During possession of the ECML on 28/29 November 1981 the girders were lifted from railway wagons using two 75tonnes capacity railway breakdown cranes (from Doncaster and Healey Mills) working in tandem.

They were then lowered onto skates on a roller path and moved across to the new embankment.

•The steelwork for the two river spans was then assembled, fitted with a temporary extended nose and hauled over the river.

•The spans were pulled across the river using winches fixed on the south embankment.

•A further unusual operation was the use of a barge for delivering rock armour to place on the riverbank adjacent to the pier, to provide scour protection.

•Here is the finished structure. Note, the HST is on the original ECML. It is not about to run into the ballast pile.

•The civil engineering main contract work was complete on 18th October 1982, more than 2 months ahead of the contracted completion date.

•However, monitoring of the un-piled section of embankment north of the River Aire Bridge, between the embankment supported on piles and the Temple Hirst Road was continued because the data showed ground water pressures continued increasing when they should have been dissipating, raising the risk of failure. The reason was not understood.

To ensure the railway would operate at 125mph from the start of the May 1984 timetable this length of the embankment was removed and rebuilt on piles, between March and June 1983.

The main civil engineering contract included placing 375mm of ballast on which the track would be laid.

•This was brought to Hambleton railhead and stockpiled ready for placing as sections of embankments and cuttings were complete.

The final task for the main contract was to compact the ballast to a finished tolerance of + 0 to –15mm to suit the tracklaying process.

•These are some of the main contractor’s (A Monk & Co.) and the BR resident engineer’s teams based at the Hambleton site offices who delivered the main construction contract.

Tracklaying was carried out by the BR’s Divisional Engineer, Leeds team.

•Precast concrete sleepers for the tracklaying were delivered and stockpiled at the Hambleton railhead in preparation for the tracklaying.

•A temporary rail connection was installed to join the railhead to the new Diversion alignment for tracklaying trains.

180m lengths of long welded rail were delivered to tracklaying sites on special trains.

Pairs of rollers set 10ft apart were laid on the ballast at 20ft intervals along the designed alignment.

•The rails were lowered from the long-welded rail wagons onto the 10ft gauge rollers using a purpose-made wagon.

•This is the rail laying train in action.

•The rails were pulled from the train onto the rollers using a Unimog fitted with balloon tyres to minimise disturbance of the ballast.

•Before being completely drawn off the train the first pair of rails was clamped to the next pair. This process was repeated until four pairs of rails were on rollers on the ballast.

•The rails were then jacked up, the rollers removed, and the rails laid on the ballast at 10ft-gauge.

•The rollers were removed using a special jacking trolley, picked up and moved forward to receive the next pair of rails.

Further pairs of rail pairs were then drawn from the train over the top of the rails on the ballast using special railhead rollers.

Using this process, a total length of 1800 metres (1 mile) of rails were laid at ‘ten foot’ gauge to the correct alignment.

Sleepers were delivered to the work front on wagons in three layers of 56 sleepers along with a self-propelled tracklaying gantry.

The gantry has hydraulic frames that enable it to raise itself off the delivery wagon, expand to straddle the sleeper wagons and fit on the ten-foot gauge rails at each side of the train.

The gantry lifted each layer of 56 sleepers from the train, carried them into position and laid them as two 28-sleeper panels, ready to receive the rails.

The rails on each side of the sleepers were then transferred onto the sleepers using this hydraulic machine.

•Insulators were placed on the sleepers and the rail fastenings were then driven into position with another machine.

An important first for the project was the design for the 125mph junction at Colton Junction, seen here being trial assembled at Taylor Brothers before delivery to site.

The turnout length from switch to crossing nose is approximately 89metres, the curve radius through the split-equal junction is 6000metres, the turnout crossing angle is 1 in 32 and there is a 1 in 17 switch diamond crossing in the centre of the junction.

Special lifting beams were used for laying in the long switches to avoid damage during installation.

Colton Junction was commissioned in October 1982.

•Progress was reflected again, in the 1982 Christmas card.

Signalling relay and equipment rooms were built at Hambleton, Colton and Temple Hirst Junctions, as part of the main civil engineering contract.

This photograph shows the building at Hambleton with a materials train coming from the railhead onto the Diversion.

The signalling work was carried out by Westinghouse Brake & Signal Co. Ltd and commissioned in stages to fit the opening of sections of the route.

It was installed, tested and approved under the direction of BR Eastern Region signal and telecommunications engineers.

The following images have been taken from a video of the signalling work produced by the late Frank Dean.

Cabling and other signalling items were taken to site by train.

Signalling equipment cases were delivered to site by rail and lifted into position.

Signalling cables were run into the lineside concrete ducts.

•The whole signalling system was wired and tested.

•The whole signalling system was wired and tested.

And after successful testing was commissioned, ready for trains to run. .

The first passenger train travelled on the Diversion on 2nd January 1983,between Colton and Hambleton Junctions, north of the Leeds-Selby Line.

From Hambleton it travelled to Selby via the single track bi-directional 40mph North-East Curve.

On Thursday 29th September 1983 a ceremony took place at Temple Hirst Junction to celebrate completion of the whole route.

The railway formally opened to traffic on Monday 3rd October.

The railway had been completed within budget, 3 months ahead of programme.

•Here an HST is photographed travelling south through the 125mph Colton Junction.

And here, a northbound express is caught at speed heading north between Bishop Wood Road and Bishopdyke Road.

•The most significant change to the Diversion since its opening is electrification in 1990, as part of the ECML electrification project.

This is at Colton photographed exactly 40 years after the opening ceremony held at the south end, at Temple Hirst on 29 September 2023. .