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Big Chute Marine Railway

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, and is overseen by federally operated Parks Canada.

History

In 1914, contracts were let to have 3 locks built to connect the Severn River to Georgian Bay; at Port Severn, Big Chute, and Swift Rapids. With the start of World War I, however, there was a shortage of manpower and resources. Lock 45 at Port Severn was nearing completion, so it was finished as a small, "temporary" lock (it remains in use to this day). The locks at Big Chute and Swift Rapids were not completed, with "temporary" marine railways being built instead. The original Big Chute Marine Railway was completed in 1917, and could only carry boats up to 35 feet long, preventing navigation by large commercial vessels. The marine railway at Swift Rapids was completed in 1919, using the same plans as the Big Chute railway.

In 1921, plans were once again made to build three locks at Big Chute, to be part of a new section of canal which would take boats from Big Chute and rejoin the existing waterway downstream from the Little Chute, avoiding the fast water in the Little Chute. However because of the post war recession the scheme was put on hold once more, although remains of the beginning of the dams required to maintain the water levels can still be found in the surrounding forest. In 1923 the original railway at Big Chute was replaced, as the size and number of boats had increased, with the second carriage being able to carry boats up to 60 feet long. The 1923 carriage was used up until around 2003, on days of extremely heavy traffic, or as a backup for the new carriage. Although the old carriage is no longer used, it remains on display.

In the 1960s surveys of the area were done yet again. The old, outdated railway at Swift Rapids was replaced with a single conventional lock in 1964, and plans were made for a single lock at Big Chute. Before construction began the Sea Lamprey, which had been devastating the fishing industry in the Great Lakes, was found in Gloucester Pool—at the bottom of the railway—and plans were put on hold. Several impractical ideas were suggested, but no practical solution could be found. By the end of the 1960s the old marine railway could not keep up with the amount of boating traffic in the area. Long lines formed at either end of the railway, with waits often being overnight. Research was done to find a way to prevent the migration of the Sea Lamprey into Lake Couchiching and Lake Simcoe, while still effectively increasing the flow of traffic. A biologist sat at the bottom of the railway for days, checking the bottom of boats that locked through, and finally saw a lamprey attached to the bottom of a boat. The lamprey fell off after less than 6 meters, so the railway was determined to be effective at preventing the Sea Lamprey's migration. In 1976, under the Government of Pierre Elliot Trudeau, it was finally decided that a new, enlarged railway would be built. The current carriage was opened to the public in 1978, and can carry a boat up to 100 feet long. It cost $3 million to build .

Operation

The vessels are floated into the cradle, which is approximately 35 metres (80 ft) long by 8 metres wide. Four 200 horsepower electric motors provide traction by cable. It can transport up to a combined total of 90 tonnes (75 tons) in weight. In this enlarged version the increased weight is borne on a dual track which keeps the carriage level (the front wheels are on a different track than the back wheels, with the front of the carriage on the upper tracks). Boats rest on the bottom of the carriage, and webbing slings are provided to support boats safely and prevent them from tipping. The old system has been decommissioned by Parks Canada, to conform with modern safety standards, although the old tracks and carriage still remain. The last operation of the old system was in 2003.

The sea lamprey

After the Swift Rapids Marine Railway was demolished in the mid 1960s, the marine railway at Big Chute was to be replaced as well. However, before this could be done a population of lamprey eels were 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 1978 to accommodate the increase in boat traffic. Up until 2003 the original marine railway was still occasionally used, when the new system would break down, or during periods of high boat traffic.