Lean on me

English: An APT at The Railway Age in Crewe. P...

English: An APT at The Railway Age in Crewe. Photo by G-Man * Oct 2006 (Photo credit: Wikipedia)

As any pinball player knows, a bit of tilt can be a very good thing. Too much, and it’s game over. When it comes to Technology, getting that tilt right is even harder.

My mother suffers from terrible seasickness. When we used to get the ferry over to Ireland, she would start being sick as soon as we left the harbour wall and she wouldn’t stop again until we were firmly docked at the other end.

Sir Henry Bessemer was a man after her own heart. He recognised the problem of seasickness and tried to devise an ingenious solution. He understood that the cause of seasickness was all the rocking and rolling of the cabin. If one could eliminate that, the passengers could enjoy a smooth ride. His solution was to mount the saloon independently of the ship, the SS Bessemer, on gimbals. Whilst the ship sailed along, a man watched a spirit level and pulled a lever to keep the saloon level.

Swinging Saloon Steamer Bessemer, 1875 (1)

Swinging Saloon Steamer Bessemer, 1875 (1) (Photo credit: Marcel Douwe Dekker)

Unfortunately for Sir Henry, it’s not a great idea to have something rolling around in the middle of a ship as it makes it very unstable and difficult to steer. That’s why oil tankers have baffles to stop the oil sloshing around. The maiden voyage was a disaster. The ship crashed into Calais pier not once but twice because of the instability of the ship.

On land, at least you don’t have the vagaries sea level to worry about which ought to make tilting things easier. In the 1970s, British Rail set about devising a tilting train to increase the speed of the rail network. France and Japan had leapfrogged Britain with the TGV and the bullet train.

If the tracks were completely straight, going fast would not be a problem. Unfortunately, they have a habit of bending to avoid things like hills, lakes and the sea. As any motorcyclist knows, if you want to go round a corner fast, the best thing to do is lean over. British Rail’s answer to this was the Advanced Passenger Train (the APT).

The train Used a series of sensors to measure the telemetry of the train and a set of hydraulic rams to lean into the corner. Also debuting on the Advanced Passenger Train was an incredibly sophisticated braking system which allowed the train to brake within the existing signal network. Unfortunately, all this sophistication was the APT’s downfall. They were incredibly unreliable in service and there were complaints from some about motion sickness.

Big Ben

Big Ben (Photo credit: Wikipedia)

Sometimes when you are making advances in rail technology, the last thing you want is any tilting. When engineers undertook the Jubilee line extension in 1994, they were painfully aware of some of the challenges that faced them.

One of their biggest headaches was the station opposite Big Ben. Everyone knew that Big Ben had been built on perilously shallow foundations. Indeed, on its completion, it started to lean to the North. If the Jubilee Line engineers came along digging a big hole next door, there was every chance the tower could topple into the Thames, which would not make great PR for the project.

In order to prevent any further tilting, they injected tubes of concrete in a star shape around the base of the tower. They injected concrete through holes in these tubes to stabilise the soft earth. During the project, they measured the exact angle of Big Ben regularly and if there was the slightest hint of a tilt, they injected more concrete. The Jubilee Line extension had its problems during construction, but a leaning Big Ben was not one of them.


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