To be fair, Shore Road pumping station is difficult to reach. Network Rail’s project manager Simon Barraclough and his colleague Behnam Sarani had been doing battle with their belligerent satnav that had already succeeded in sending them on three circuits of Birkenhead and was determined to have them drive back down through the Mersey tunnel to Manchester.
Back in the 1880s the engineers of the time had slightly weightier problems to deal with. The Mersey railway company aspired to drive a tunnel under the river through permeable and fissured sandstone. They knew that they would encounter large quantities of water and this presented a major challenge with the real possibility of the tunnel being inundated if not carefully controlled.
Their solution was to drive three tunnels – the railway tunnel, a tunnel for ventilation and one for drainage. In the end, the ventilation and drainage headings were combined under the deepest part of the railway tunnel.
The drainage scheme involves a deep-level heading driven on a rising gradient from each side of the river meeting at a central high point just below the main tunnel. At the Birkenhead and Liverpool banks, two deep shafts were sunk to take the water that flows back from the centre. Both are around 170 feet (52 metres) deep. The Liverpool shaft is 15ft (4.5m) in diameter, the Birkenhead shaft 17’6” (5.3m). Pumping stations were built over the shafts and water has been pumped out continuously ever since.
The Shore Road pumping station in Birkenhead is a tall, narrow but imposing building set back from the road. There is a constant sound of rushing water and the hum of heavy machinery. Just inside the main entrance, the first impression is of gantries, handrails and steel latticework, all set in a cavernous and labyrinthine structure.
Looming silent and dark over all the modern paraphernalia are the remains of the original beam pumping engine occupying the vast height of the building. Up on an intermediate gallery the dial of the Hardings Improved Counter shows that it stopped on stroke number 0061362.
Of the shaft there is no immediate sign. But lean over the handrails, peer down through the gratings and it’s a different matter! And it’s a sharp pull back from any temptation to linger on industrial archaeology. There is work going on in the shaft. Hammering, flickering lights, voices echoing, radios crackling, and down, down, way down, almost out of sight, is the
gently heaving limpid black water in the sump 170 feet below.
The modern pumps are, of course, electrically powered. They are heavy submersible machines that have to be lowered down the shaft from a permanent gantry. Once upon a time it was possible to reach the water in the sump via a precarious arrangement of timber staircases and landings. Each staircase was very steep – about 75° – and had only a rudimentary rope handrail.
Coupled with the fact that the shaft is, by definition, a confined space and that the timberwork was in poor condition, it is not surprising that the staircase access fell into disuse.
But, on the face of it, is there any real need to get down there? A combination of retail outlets and fire regulations have forced a revisit to the stygian depths.
Retail outlets sell stuff. Stuff is wrapped in packaging. Packaging is discarded. Fire regulations say that there must be no litter bins in the Merseyrail Loop so packaging becomes litter. It is dropped on the platforms and finds its way onto the tracks. It gets blown into drainage gullies and eventually, courtesy of the magnificent Victorian drainage headings, lands up in the sumps at the bottom of the shafts and then, very quickly, into the drainage pump intake filters. These become clogged and the pumps overheat and eventually burn out. The damaged pumps are then winched all the way to the surface – a very complex process – replaced or repaired only to be lowered back into the litter soup in the sump.
So there is an imperative to reach the lower part of the shaft so that pumps can be serviced without having to be hauled all the way to the surface. In parallel there is work going on to limit the litter issue generally.
Simon explains: “The scheme was forever on the ‘rather tricky’ pile, but it was developed by Murphy as part of their framework agreement with Network Rail. It was such specialist work that a single negotiated tender was deemed the best way forward.” Murphy used Opus Design to survey and draft a scheme for a new access arrangement that would meet modern safety requirements. Fabrication was by Structural Fabrications Ltd.
“Right from the start this has been a complex project. It takes place in amongst a fully operational pumping station with water being pumped out of the tunnels continuously.” Despite the huge dimensions of the shaft, the access is very restricted. With the existing machinery, its maintenance equipment and the ever-present remains of the old pumping engine the only way down is via a 900mm x 900mm grating.
Fortunately, Murphy operates a roped access team for use in such tricky projects. All their staff are confined space trained and are IRATA (Industrial Rope Access Trade Association) qualified. For them this is their bread and butter.
Top down approach
There are eleven individual landings. Each one of the top six landings is supported by a pair of massive timbers set into the unlined sandstone walls. These have survived decades of damp and are in good condition, although the same cannot be said for the rest of the staircase materials. The timbers have been used as the basis for new galvanised steel landings. Pockets have been taken out of the sandstone at the ends of the timbers to allow main beams to be landed in the sandstone and also bolted to the timbers.
Once fixed, they are bricked in using a quick setting compound that can cure even in these hostile conditions without being washed away. Terracaulk 40AF by tecroc is a purpose designed Portland cement, fibre and polymer reinforced, shrinkage compensated mortar.
Components for the rest of the landings, and for the staircases, are then built on from there. Work has proceeded from the top down with each subsequent landing and ladder being suspended from the one above. Each old staircase is demolished to give space for the new assembly. This goes on down to level five which is where a side adit enters the shaft. A special landing arrangement will give access from the shaft to the adit which in turn leads to the main railway tunnel. From level five downwards, the arrangement alters and all further landings are suspended from this point to the water level below.
Martin Taylor of Murphys shrugs his shoulders. “Access to the site is so restricted. There’s no parking in the street and there is just this one small courtyard which has to be kept clear for access to the operational pumps.”
Thursday is delivery day, when a fresh load of steelwork arrives and is sorted into batches. Each piece is then lowered via a Tirfor winch through the narrow grating with long items up-ended and threaded through.
By the end of August the final staircase will be in place and the Murphy team will move on to work on to their next assignment on a Cumbrian rail viaduct. The total cost of the works will be in the region of £350,000. It is a substantial and fascinating project that will be forever out of sight of the travelling public. The pumps have to run. Without them, and their counterparts on the Liverpool bank, the railway tunnel under the Mersey would be inundated exactly as the Victorian engineers predicted.
The attempt to return to Manchester was just as fraught after the obligatory circuit of Birkenhead.