Big Chute Marine Railway
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Big Chute Marine Railway is a ship lift at Lock 44 of the Trent-Severn Waterway in Ontario, Canada. It works on an inclined plane to carry boats in a cradle (without a filled tank) over a change of height of about 18 metres. It is the only marine railway of its kind in North America still in use.
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[edit] History
The first system was built in 1917 instead of the more usual lock, which was not completed for financial reasons because of the outbreak of First World War. (The same thing happened at lock 43 in 1919, where the Swift Rapids Marine Railway was built.) These original marine railways carried only small boats, preventing navigation by large commercial vessels. The modern, larger railway was built at Big Chute in 1977, while the railway at Swift Rapids was replaced by a conventional lock.
[edit] Operation
The vessels are floated into the cradle, which is approximately 35 metres long by 8 metres wide. It sits on an angled frame so that when it is drawn out of the water onto the sloping track it remains level. Four 200 horsepower electric motors provide traction by cable. It can transport up to a combined total of 90 tonnes in weight. In this enlarged version the increased weight is borne on a dual track and webbing slings are provided to suspend boats safely, without the risk of their toppling over. The old system has been decommissioned by Parks Canada, to conform with modern safety standards, although the old tracks and carriage still remain.
[edit] The sea lamprey
After the Swift Rapids Marine Railway was demolished in the mid 1960's, the marine railway at Big Chute was to be replaced as well. However, before this could be done a population of lamprey eel was discovered in Gloucester Pool, on the downstream side of the lift. They had been migrating into the Great Lakes from the Saint Lawrence River and were considered a big problem for the fisheries as they were native to the oceans, and were killing off all of the fresh water fish. The Canadian government decided to delay building the lock while a solution was considered.
After a few impractical ideas were thrown around, a marine biologist was hired to examine the old marine railway and see if it was effective at stopping the lamprey migration. The biologist discovered that the railway was a good preventative measure against the migration of the lamprey into the rest of the Trent-Severn Waterway. Unlike many types of eel, the lamprey could not survive outside of water and so could not migrate any further into the system. As a result, the old mechanism was retained, and the new one built in 1977 to accommodate the increase in boat traffic. Up until 2004 the original marine railway was still occasionally used, when the new system would break down, or during periods of high boat traffic.
