Meadowhall Mush

This week, the Sheffield Star published an article about why the Meadowhall site for the Sheffield HS2 station is a bad choice – but the problems it discusses are repeated in numerous other places along the line. And what’s more HS2 Ltd claim that in spite of these problems, they can come up with a Phase 2 route which is “fully costed and within budget” in time for the Secretary of State to make a decision this year.

Adrian Millward, former assistant chief engineer at Sheffield City Council, told the Star that the HS2 route follows a three-mile fault of fractured rock, posing a huge and uncosted engineering challenge.

Describing the ground as “shattered”, Adrian said about the site “If I was to pick a spot not to build a station, that would be it – and HS2 is bang on top of it. You could not build in a worse place. The rock is shattered, flooded and connected to old mine workings, forming what is essentially an underground reservoir. Drill into it and it turns to mush. I think they have underestimated the difficulty of building a new viaduct at Tinsley and I don’t think they’ve taken the cost into account.”

Like other parts of the HS2 route, the area around Sheffield has numerous mine workings underground, many of which are not recorded, due to the long history of coal working in the area: similarly in Cheshire, the west leg of HS2 has problems with former salt mines.

According to the Star, Tinsley Viaduct, which carries the M1 and runs parallel to the proposed HS2 route, had to be strengthened at a cost of 16 times the build cost. Similar problems – or worse – are likely to hit any HS2 viaducts. Unlike the motorway viaduct, which can flex, an HS2 viaduct will need to be more rigid, due to the speed of the trains.

An HS2 spokesman claimed that they welcomed more information about technical matters from “relevant city regions”, but with the decision on the route due to be made in the autumn 2016 (delayed and delayed again since the original announcement due in autumn 2014), they are running out of time to work things out. And with the spokesperson also claiming that the HS2 decision will be both “fully costed and within budget”, one wonders if they are as hopeful of the arrival of Father Christmas later on.