Hyde Park Now-King's Cross tunnels & canal aqueduct

King’s Cross tunnels & canal aqueduct

The King’s Cross upgrade is a complex project because of the proximity of the adjacent tunnels known as Gasworks to the main line station and its platforms. This is why the layout was hugely rationalised in the seventies – in order to provide more flexibility – however that came with certain caveats which have only been appreciated mostly this last decade – and this is why Network Rail began the King’s Cross station approach works as part of its East Coast Upgrade. But even despite the improvements there are still many restrictions on how the layout can be modified or enhanced – and its all to do with the Regent’s Canal! In this post we look at the ongoing station upgrade and the problems the canal poses for the railway.

Just to mention this is the first part of a two-parter. Also there’s a certain amount of other pictures besides the Regent’s Canal aqueduct! Its to provide continuity and context well as show how some of the other bits of the King’s Cross upgrade progressed. You’ll notice there’s some shots of the Deltics too! Yes, why not! Its all related isn’t it?

Hyde Park Now-King's Cross tunnels & canal aqueduct

King’s Cross in 1955 with A4 Golden Fleece and its train arriving. The Ebonite and Metropolitan (Caledonian Road) towers can be seen in the background – but what’s more interesting is even with this considerably elevated view the Regent’s Canal simply cannot be seen. Yet the canal occupies a huge space even on the railway too. Its because the canal passes through here on an aqueduct almost totally hidden from view! Source: York Mix

Much like people are surprised to find a canal right next to Paddington station, both King’s Cross and St. Pancras also happens to be two other London termini that have a canal right next to their running lines, thus London has three termini with this somewhat unusual arrangement. From the 1830s to the 1850s when these railways arrived in the city, the presence of the canal at each of these three locations determined the alignment and extent of the new terminus area that would be built, thus each of the railways’ builders, (Brunel, Barlow and the Cubitts) employed a different approach to the building of their London termini, taking into consideration the canal at these locations. (Incidentally Victoria station too was originally constrained by a canal but since its no longer the case we shan’t consider it.)

Its likely why Brunel built his new London terminus at an angle that was quite obtuse compared to the remainder of his Great Western Railway which generally headed along an east-west axis. Certainly Paddington is noted for being a south facing terminus with a station throat that turns sharply westward, and its clearly because the Grand Junction Canal had a hand in this state of affairs. Actually the first terminus built by Brunel was temporary and existed from 1838 to 1854 and that one was at least at an angle more suited to the railway’s western alignment. However this early station ended right about where the canal was, and Paddington station itself being an extension onward from that earlier terminus, had to be turned to the south simply to fit alongside the canal that led to Paddington basin. The canal’s presence at Paddington however wasn’t any sort of major problem compared to the other two stations as we will see.

Hyde Park Now-King's Cross tunnels & canal aqueduct

How King’s Cross looked in the BR blue era during the 1970s and the class 55s headcode panels replaced with twin lights! The famous signal box soon made way for a new power box nearby. Note the two nearby towers in the distance – the Ebonite tower and the Metropolitan Cattle Market’s clock tower. The former was once one of London’s tallest buildings and demolished in the early 1980s despite opposition. The latter still survives. Source: Twitter

At King’s Cross and St. Pancras, the Regent’s Canal was in fact an impediment to these new London terminuses because its route lay diagonally across the course these two new railways. As a result William Barlow came up with quite ingenious solutions that in fact shaped how St. Pancras station would be built. The St. Pancras you see today is built as it is because of the Regent’s Canal!

The same can be said for King’s Cross, however compared to St. Pancras, the canal happened to be an even bigger problem. The Great Northern railway wanted a grand station (King’s Cross at the time of its opening was the biggest in Britain) and one that was completely level with the adjacent streets. The land they had bought however lay immediately to the south of the Regent’s Canal, and the New Road (now Euston Road) in turn determined just how far south the new station could be built.

As a parable with regard to what and what not to do at King’s Cross, the Midland Railway’s engineers were only too aware of the presence of the nearby Regent’s Canal (as well as the problems the Cubitts had building their station) thus the Midland’s engineer William Barlow made sure the new railway was not unduly affected by the canal. This was achieved by ensuring the main approach to St. Pancras station was by means of a viaduct which carried the lines sufficiently across the Regent’s Canal, whilst the tunnelled route to the widened lines (and which now forms the main Thameslink route) the engineers were savvy enough to ensure this went deep enough in order that it passed well below the Regent’s Canal. Actually the Midland’s engineers needn’t have worried too much about their tunnel because the Regent’s Canal at this point is at a higher elevation that at King’s Cross! They also began the approach gradient from the north quite a way back which meant the gradients were acceptable in regards to the locomotives’ capability in the 1850s.

Hyde Park Now-King's Cross tunnels & canal aqueduct

It isnt a Victorian view of King’s Cross St. Pancras but rather one taken around 2015ish. One can see how the canal passes immediately over the tracks just outside of King’s Cross station. St. Pancras lock can be seen on the right, whilst Camley Street can be seen passing underneath the railway just above the lock. These two structures (and the water tower in between) are referenced to in the next few pictures. Source: Network Rail

What the above picture does is to illustrate exactly how the Midland Railway had advantages compared to the Great Northern Railway, and from this one can see how much land St. Pancras has between its station and the Regent’s Canal (which it passes over just out of view to the right) whilst King’s Cross is totally constrained by the canal passing almost right across its station throat. St. Pancras lock can be seen at right. This in fact became the joker in the pack for the Cubitts and King’s Cross station because the canal was lowered by more than six feet in elevation – something the Great Northern Railway could have done without, because it meant they had to build an rather awkward rail approach to their new station at King’s Cross.

Originally the Midland railway had decided upon building tunnels under the canal too for their new approach to their London terminus. After seeing what had happened at King’s Cross the Midland Railway had a big change of plans. But that involved the controversial purchase of Agar Town, St. Pancras Church and its vast graveyard. The Midland’s purchase of the St. Pancras burial sites made for a national scandal because more than 10,000 bodies had to be dug up. As the saying at the time went ‘Old St. Pancras churchyard was invaded, and Agar Town almost demolished.’ (British History.)

Hyde Park Now-King's Cross tunnels & canal aqueduct

Here’s a composite photograph from the St. Pancras water tower taken some years ago. Its not a true panorama as I took the images quite a few moments apart, not intending to create a pano! The light and clouds are somewhat different as a result.

The stitched together pano (shown above) at least depicts the situation from roughly an eye level viewpoint of the canal and the Midland Railway. On the left is the Regent’s Canal on the right side is the Midland Railway route (the Southern’s High Speed tracks are nearest to camera) with Camley Street bridge in the lower right corner. St. Pancras lock is just behind the yellowish building in the near foreground at left (its not actually yellow its the sun shining on it!) Its the road that achieves the greatest elevation difference because it is practically level with the Regent’s Canal and then dips sharply to go under the Midland railway itself.

King’s Cross station is about where the two pictures meet (the middle of the pano in fact) but it cannot be seen because its lower down in elevation, not only that the new buildings that have cropped up around King’s Boulevard and Pancras Square now obstruct any view of the Great Northern Railway’s terminus. One can also see the former railway viaducts that form part of the Coal Drops Yard complex. These are essentially at the same height as the Midland railway’s route on the opposite side, which if one walks along the towpath along the southernmost of these at Coal Drops yard, one can see how much elevation the Midland Railway has already gained even though the canal itself too rises through St. Pancras lock to the north.

Hyde Park Now-King's Cross tunnels & canal aqueduct

The huge bugbear for the Great Northern’s (and its successors, LNER, BR, Network Rail) King’s Cross station has always been the Regent’s Canal.

In the above image King’s Cross station’s twin roofs can be seen here along with the Midland’s gothic St. Pancras Hotel in the background. The Regent’s Canal has an advertised depth of 8 feet (it varies however depending on the thickness of the mud that’s down there.) That plus the depth of the aqueduct beneath it which is around three feet for its supporting structure and then there’s its base (the actual plates the canal’s bed sits on) which means the surface of the Regent’s Canal is somewhere around ten feet above the tops of the railway tunnels. Not a lot is it?

One would wonder why the Great Northern did not build their station where St. Pancras was. The problem it seems was the land was not available. King’s Cross was built on the site of the London Fever and Smallpox hospital, which the locals were only too glad to get rid of. Thus it was the circumstances of the time that brought the Great Northern to where it ended at. Why did the Great Northern look at solutions like raising the canal several feet and moving the lock to where Maiden Lane bridge is? That would have given the company a huge confidence booster because they would then have practically unlimited clearance in their new tunnels!

The explanation is although vast canal basins were built here by the Cubitts (e.g. the King’s Cross Good Yard complex in 1862) the canal was already established hereabouts and there were other basins to consider. For example along the west side of the King’s Cross station site there was a canal basin which served the adjacent Imperial gasworks. This basin had been there since the 1840s or maybe even earlier, thus to even raise the levels of the canal they would have had to bring up the level of that basin too and the topology of the land just didn’t allow that. Thus raising the canal was practically a no-no. As the map below shows the extent of King’s Cross station was practically dictated by the canal!

Hyde Park Now-King's Cross tunnels & canal aqueduct

The King’s Cross gasworks canal basin immediately to the west of the tunnels and station area. I’ve coloured the map to highlight the extent of the canal. OS map of 1893-95. Source: National Library of Scotland

Ultimately the Cubitts decided their new railway could just squeeze through the very tight clearances demanded at King’s Cross. They managed it of course but over time the arrangement has indeed become problematic and its only with great ingenuity the present planners and engineers have been able to squeeze more out of the King’s Cross layout as well as ease the gradients underneath the Regent’s Canal itself.

With these problems in mind, in 1849 it was decided the Great Northern’s railway should instead end at a terminus north of the canal. This they did – and it was known as Maiden lane station a- temporary stop gap while the engineers pondered what to do with the proposed King’s Cross terminus. in time the GNR’s engineer, Joseph Cubitt put forward plans for an aqueduct and tunnels to enable the new line to reach its proposed terminus by the New Road from Paddington to the City. The Great Northern wanted an imposing and level facing structure (from street level straight onto the platforms) thus the solutions devised were commendable but have given problems to this day.

The tender for the temporary Maiden Lane station was submitted to Herapath’s Railway Journal in December 1849. This temporary terminus would give the Cubitts time to sort out the problems the Regent’s Canal had presented in terms of achieving the original objective of a terminus to be sited by the New Road at King’s Cross.

Let’s look at the Midland railway’s route and see how they solved their side of the problem…

First of all the Midland decided instead of building tunnels under the canal, they would instead build an elevated railway terminus and that would take the tracks over the Regent’s Canal. However had they kept the tracks level from the canal to the new terminus the platforms would have been something like thirty five feet above street level. It would have been extremely expensive, so they decided on a gentle gradient down from the canal in order to make their new terminus more of a realistic option. In that respect the company achieved a construction where the tracks stood 17 feet above street level. They did indeed build tunnels under the canal for the connection to the Widened Lines however since there was no station on this section the tunnels could burrow deep enough to pass under the canal (as well as deep enough under St. Pancras itself so as not to affect the terminus’ foundations.)

Hyde Park Now-King's Cross tunnels & canal aqueduct

One can see the gradients out of St. Pancras by watching the trains come and go! Although I have not been on the station’s platforms since its reconstruction and introduction of high speed services, this long zoom shot taken from the public areas, and even if slightly blurry, does at least show a Class373 coming down the gradient into the station. By the way this was one of the last 373s to use St. Pancras.

Hyde Park Now-King's Cross tunnels & canal aqueduct

Camley Street bridge can just be seen in this view from the footbridge over the Regent’s Canal. Note the water tower from which I took my panorama shown earlier. The Midland Railway’s route rises continually from St Pancras towards the canal and beyond.

The Midland Railway’s route out of St. Pancras (currently used by Southern High Speed, Eurostar and East Midlands Railways) in fact has a gentler gradient which gains enough height to cross over the Regent’s Canal. One of the railway’s bridges (seen in the background, above picture, at left across Camley Street) shows St. Pancras itself isn’t very much above the elevation of the Regent’s Canal either, however the railway gains enough elevation to cross the canal as the next picture shows.

Hyde Park Now-King's Cross tunnels & canal aqueduct

As can be seen from this view the Midland’s route out of St. Pancras is on a constant gradient (note the water tower again and how the line has ascended since the previous picture) thus it gains sufficient climb to be able to pass over the Regent’s Canal with ample headroom for the barges. St. Pancras’ famous train shed can be seen in the background along with one of the station’s gothic towers.

Building the three tunnels and canal aqueducts at King’s Cross:

In terms of building the King’s Cross terminus, its tracks would be at an elevation of 51 feet above sea level. However the surface of the Regent’s Canal immediately to the north is 70 feet in elevation. One might think there’s plenty of headroom in fact for the railway to pass under, but that wasnt the case. In essence there was roughly ten foot of difference in height between rail level and the bottom of the canal. One could never get a full sized train through that sort of gap! To make things worse, the canal had to be built on an aqueduct that spanned the new railway. The arches, supporting brackets and topmost plates for this happens to be around two foot three inches in depth, thus the minimum clearance that would be possible had to be somewhere in the region of seven feet nine inches (roughly 2.34 metres) which isn’t a lot in fact.

Hyde Park Now-King's Cross tunnels & canal aqueduct

As the above description shows, the Regent’s Canal ‘presented problems of limiting gradients and clearances…’

Thus the Cubitts were left with no option but the take the railway under the canal via a pair of gradients either side. That on the north side was generous fortunately, however that on the southern side, because the tunnels emerged straight into the King’s Cross station throat itself, had to be quite steep. The amount of distance from the tunnel portals to the bottom of the inclines is as follows (figures approximate):

Eastern Gasworks tunnel Total distance: 53.86 m (176.72 ft)

Middle Gasworks tunnel Total distance: 45.64 m (149.73 ft)

Western Gasworks tunnel Total distance: 37.66 m (123.56 ft)

However even to start the gradients immediately at the tunnel mouths would have meant even more steeper slopes, so the gradients in fact began further back (as they still do to this day) in order to give the trains a bit more leeway as they descended into the tunnels and underneath the Regent’s Canal. According to LNER railway documents the length of the downward gradients off the ends of the platforms totalled 146 yards. This is clearly an approximation however because the LNER too say the sections within their three tunnels were 153 feet in length – when it seems they actually vary.

No doubt if one has been at the end of the platforms at King’s Cross watching the trains arrive and depart or maybe waiting for a steam special (or the last HST to have used the station, whatever) one will hardly have failed to notice how the trains descend quite sharply into the tunnels themselves. Even with the recent rebuilding and upgrade of the station throat, the trains still descend from the platform ends into the tunnels much as they always have.

Hyde Park Now-King's Cross tunnels & canal aqueduct

This picture I took during the LNER InterCity 125 finale at King’s Cross on 21st December 2019. Its not a brillliant shot however it does show the steep gradient from beneath the canal itself up into the station environs. Power car 254 029 is nearing the bottom of the gentle incline from the north before tackling that very short section of 123 feet (just over 37 metres plus that little bit extra up into the station throat) the total length of this rise being not much more than a couple of those Mark III carriages the HST is pulling!

It must be said these tunnels and their gradients have very unfortunately been the cause of a number of accidents over the years, some with fatalities, no doubt caused by trains failing to tackle the gradients and sliding back (across points for example) into other trains or something of that sort. Wikipedia has a list of accidents at the station and its clear a good number of these can be attributed to the gradients immediately north of the station. It has also been said (as in the example of the 1945 accident report) the Regent’s Canal aqueduct leaks thus one can deduct this sometimes causes the rails to be slippery.

In terms of construction of the three tunnels its difficult to know exactly how these were done as there’s very little to go on. In terms of the first tunnel (the middle one) the Cubitts were well aware that there was no way anyone was going to build a tunnel immediately north of King’s Cross station and have the railway ready for opening by the time of the Great Exhibition in 1851 as they had hoped. However it seems the canal was closed for a week (its annual closure for cleaning out and the rest of it and this would be the period where the contractors were able to quickly dig out and built the aqueduct in question, and then complete the tunnel beneath once the canal had been filled.

The bit between the tunnel mouth (80 feet or around 24 metres) and the Regent’s Canal was let to a contractor by the name of Mr. Jay (History of the Great Northern Railway.) Incidentally, this guy, Mr. Jay was in fact the same contractor who was awarded the work for the building of the early 1860s Metropolitan Railway tunnels between Gower Street and Clerkenwell, as well as the interconnecting tunnels to and from the Widened Lines. I cant find anything about the actual construction of the canal aqueduct or even the tunnel itself. There’s a list of contracts for the new station made during 1850, that can be read on Google Books but it sheds no light on the tunnels or the canal itself.

Hyde Park Now-King's Cross tunnels & canal aqueduct

Description of the Regent’s Canal, its aqueduct, and the railway tunnel. Source: Illustrated Magazine of Art.

There was an accident in the tunnel when part of it collapsed. This took place during 1850. As it transpires, One group of miners headed by a guy named Abel Wynne were at work building the tunnel. The temporarily dug tunnel supported by timbers, however suddenly gave way and Wynne was crushed to death. (Railway Record Volume 7.)

Before the Great Northern Railway could open its new London terminus in 1852, on the Wednesday 13th of October of that year, R.M. Laffan, Captain of the Royal Engineers, conducted for the Government an inspection of the station, the tunnel and of course the Regent’s Canal aqueduct to make sure they were all of sound construction and that the tracks and signals were in full order, before giving the railway company a certificate of full authorisation to operate its new railway and terminus. That evening the company celebrated by illuminating the station with lights of ‘a vast magnitude’ and the immense number of lights used created a ‘grand illumination.’ Services began the next morning, the first train departing at 7am for York in the presence of a huge crowd of well wishers and onlookers. (Illustrated London News 1852.)

As for the second tunnel, its mentioned in Herepath’s Railway Journal (August 18th 1877) the second was ‘one of very difficult construction.’ The contract, totalling £145,000 for the second one, was let on 27th April 1876 to a company called Firbank. It opened on 4th March 1878. Interestingly 1878 is also the date when the most recent York Road station was established, and this no doubt was due to the introduction of the new eastern tunnel.

In the second example it said the Regent’s Canal too was closed for a week to enable the works to be undertaken. (quote from Exploring Regents Canal, pub 1994, its author Michael Essex-Lopresti says its from Old and New London, Volume V, c1877, p.314). ‘during this period so strong a force of men was put upon it that between one Saturday and the next a tunnel was dug under the canal, and bricked and roofed over before the water was sent back into the canal.’ That account however seems to illustrate a somewhat easier job than it actually was.

As for the third tunnel this was built between 1890 and 1892, its total length was 1590 ft, and the length of the aqueduct section itself was 165 feet. Cast iron hog-back beams, 31 feet long, were used to span the tunnel itself, each section being three feet wide and two feet deep, and then on top of that the iron plating for the bottom of the canal would be placed. No doubt clay puddling was used as well to ensure the structure’s water tight integrity. The engineer for the tunnel was Mr Richard Johnson M. Inst. C.E. and the contractor was Henry Lovatt. Steel piles or perhaps more accurately needles, since these had pointed ends, were used in the 1892 construction as a means of underpinning the works. The underpinning system was patented in the UK by Messrs Jennings and Stannard of Westminster.

Hyde Park Now-King's Cross tunnels & canal aqueduct

Boats with people living on them (such as this) were moored directly above the railway tunnels. These were known as King’s Cross Goods Way moorings. I took this picture about 2003. Work had barely begun to redevelop the area.

It wasn’t just the Regent’s Canal that was a nightmare in terms of the third tunnel to be built but also the railway’s own goods yards and market areas immediately above the crown of the tunnel. The buildings along this section had cellars which were just six feet above the actual crown of the tunnel in places.

Michael Essex-Lopresti, in his Exploring the Regent’s Canal book (pub 1994) informs us the old walls along the canal towpath, where the railway tunnels pass underneath, used to have markings on them (no doubt for the use of the railway’s engineers) along with one word, ‘tunnels’ which was written three times – and these marked where each tunnel passed underneath the canal! Thus its evident the railway’s engineers saw the presence of the canal as something to be wary of! These markings were perhaps also for the canal’s workers who therefore took rather more care, for example when dredging the canal about these areas!

As a side note, the Regent’s Canal has a set of ARP gates. These were installed during wartime to protect any areas of London that lay lower than the level of the canal itself. The tunnels at King’s Cross too were protected by these gates. The first set of gates is by Granary Square, near where the grassed steps are. The second set of gates are by Maiden Lane (York Way bridge.)

Continued in Part Two with pictures of the aqueduct as it is seen today.