The Lock flight
at Foxton was built in 1810, and the top summit route opened four years later, celebrating its anniversary in August 2014.
A trip through the ten locks takes about 45 minutes to negotiate the 75 ft (just under 22.911m) hill and uses 25 thousand gallons of water, but if there is a queue you can be held up for hours. Boat width in the locks is restricted to seven feet (2.13m). Boats using the locks can carry a maximum load of 20 tons. With only the horse and cart for competition, the 45 minute journey (for each boat) through the locks was unimportant, even when queues extended this to several hours.
With the coming of the railways, competition was starting to bite. Fellows Morton and Clayton (FMC) wanted to use bigger boats to take coal from the north to the London factories. They promoted a take-over of the Leicester line of the canal by the Grand Junction Canal Company (see Local Waterways). The takeover was successful and FMC promised to put more narrowboats on the canal until the locks at Watford (Gap) and Foxton could be widened.
GJCCo engineer Gordon Cale Thomas was put in charge of the project. Wide locks were dismissed as using too much water from the canal's summit pound. His solution was to build a boat lift to his patented design.
100 years ago the locks were rebuilt for night use
The lift didn't normally work in the dark. Horse boats tended to stop because the horse needed its rest. By 1909 FMC steam boats were working 'fly' which meant non-stop boating 24 hours a day, with a four man crew in shifts. To accommodate these fly boats, the locks were restored for night use. The lift continued to be in use for daytime traffic until 1911.
The lift had worked well but the locks at Watford Gap were never widened, and the traffic didn't increase. This made the lift uneconomic. There were problems with track bolts pulling out of the sleepers, but nothing that could not have been overcome. The lift was capable of moving a massive amount of traffic compared with the actual usage. FMC's promise of increased traffic hadn't been fulfilled.
In 1911 the lift was mothballed to save money, the traffic returning to the locks which have been in use ever since. The decision was probably due to the need for substantial maintenance repairs on the 10 year old structure, It probably needed new cables which are expensive and the cost of keeping the lift in steam with a minimum of three operators. The fact that a fully working set of locks was available alongside the lift would not have helped. The lift was maintained for a few years, surviving the first world war, and sank into a slow decline. In 1928 the machinery was sold for scrap.
The lift was built by J & H Gwynne of Hammersmith, London. They got the job as they proposed using hydraulic power for the gates and ancillary equipment. It consisted of two tanks or caissons linked by wire rope. A steam driven winch at the top wound the rope on to one side of its drum and simultaneously let it off the other, raising and lowering the tanks. Each tank was full of water and weighed 230 tons with or without a boat. Two boats or one barge would fit in to each tank. The gradient was 1 in 4.
Using the lift.
Assuming your boat is at the bottom, you took your boat(s) into the tank. The operator would close a guillotine gate behind you and signal the engine room with a ship's telegraph. The 25 horsepower steam engine is turned on and you ascend the hill. The other tank descends either loaded with boats or just full of water. The descending tank simply sinks into the water at the bottom where the guillotine gate is opened by the operator. However, the immersion of the descending tank effectively makes it lighter in weight, upsetting the balance between the two tanks. To compensate for this, when the tank nears the top of the Incline, an ingenious change is made to the angle of ascent. The top of the slope curves off, effectively making it easier for the tank to ascend. On the leading edge of the tank, extra wheels come into contact with extra rails either side of the normal track. At the same time the rear wheels descend into a pit. This arrangement keeps the tanks upright. The tank has scrapped the wooden seals fixed on the end of each top dock. Once at the top, hydraulic rams push the tank on to the wooden seal, and the guillotine gates on the end of the tank and on the dock are opened. The horse is re-attached and off you go. The entire operation has taken 12 minutes, and could move 2 boats up and 2 down. A big saving against the time taken to use the locks.
The lift also saved a tremendous amount of water, because the only water lost was that trapped between the gates at the top.
The Foxton Boat Lift
A Brief History
A unique solution - widen the canal & save water - AKA - The Thomas Lift, The Foxton Barge Lift, The Foxton Inclined Plane, Lift Lock, or The New Locks