The Saskatchewan Railway Museum

The Saskatchewan Railway Museum


Oban Interlocking Tower

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The Grand Trunk Pacific Railway was amalgamated with the Canadian Northern by the Canadian Government to form the Canadian National Railways in 1920. Interlocking plants are a system of signals at railway crossings and junctions which are interlocked to make it impossible to give proceed (green) signal indications in conflicting directions. Nowadays, interlockers are electronically controlled and many are totally automatic. However, when they were first introduced interlockers were mechanical and manually controlled by towers such as Oban adjacent to the tracks.

Oban tower was located where the Canadian National branch line from Biggar to Battleford crossed the Canadian Pacific main line from Winnipeg to Edmonton. According to the rules of railroading, every train approaching a level crossing with another railway had to come to a complete stop and not to proceed until the crew determined that it was safe to do so, not unlike a four way stop. Another rule is that the second railway to the crossing had to build and maintain an interlocking to the standard required by the first railway. This means that the Grand Trunk Pacific (absorbed into Canadian National in 1920) was required to build the Oban tower to protect its crossing of the Canadian Pacific.

As was common in the early years of the 20th century, the Oban interlocking used semaphore signals. These signals used a mechanically controlled blade and three coloured lenses that covered a lamp as the blade moved. Three indications were possible with a semaphore signal. Proceed when the blade was vertical and the lamp green, approach when the blade was at 45 degrees and the lamp yellow and stop when the blade was horizontal and the lamp red. Originally, white lamps were used for proceed and green for approach. This practice was discontinued because it was discovered that if a red lens broke the lamp would show white and a train might proceed when it should have stopped.

The Oban tower controlled eight signals and four derails by operating levers that moved the semaphores and derails with rods and linkages located alongside the tracks. Four of the signals were home signals that were located in each direction adjacent to the crossing, the other four were distant signals located about 1/4 mile before the home signals. The derails, when open, would derail a train that ran through a stop indication preventing a major accident by causing a minor one.

To operate the tower the following procedure was used: To begin, all derails are open, all home signals are red, and all distant signals are yellow. Before any levers were moved the interlocker had to be unlocked. It was unlocked by starting a timer, the timer ran for about three minutes, once the timer ran down the interlocker was unlocked. The timer was used to ensure that the operator did not change a derail or switch under a moving train. To clear the plant for a north bound train, first the north and south bound derails were closed, second the north bound home signal was moved from red to green, third the north bound distant signal was moved from yellow to green. If the plant is now to be cleared for a south bound train, first the timer is run, second the south bound home signal is moved from red to green, third the south bound distant signal is moved from yellow to green. At some interlockers it was not possible to have the route cleared simultaneously for both north and south bound movements. If the plant is now to be cleared for an east bound train, first the timer is run, second the north and south bound distant signals are set to yellow, third the north and south bound home signals are set to red, fourth the north and south bound derails are opened, fifth the east and west bound derails are closed, sixth the east bound home signal is set to green and seventh the east bound distant signal is set to green.

Oban tower was acquired in c.1990.



Unity Express Shed

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Built for the Grand Trunk Pacific Railway (later Canadian National) in 1919. Express included small parcels and packages shipped in express (baggage) cars on passenger trains. It was the most expensive class of freight shipment. Similar sheds were used for less than carload freight (lcl). Lcl included small shipments shipped in boxcars in freight trains and went for a lower rate than express. In most small towns express, lcl and passenger baggage was handled from the same building that was often connected to the passenger station.

This building was acquired in 1993 and moved to the museum in 1994. It is currently being returned to its Tuscan red paint scheme.



Argo Station

This is a standard Grand Trunk Pacific type “E” station. It was built at Argo, Saskatchewan (southwest of Biggar) and was sold to a local farmer in the early 1960s who moved it to his farm and placed it on a concrete basement. The station served as a farmhouse until the farm changed hands in the 1990s. The station was moved to Unity where it was going to be used as a business. However, this plan failed and the station was donated and moved to the museum in 2000.

Built in 1913, this station has a waiting room, office, agent’s bedroom, living room, kitchen and bunkhouse on the main floor and two bedrooms and a storage room on the second floor. It was common practice for the railways to provide living quarters for their agent’s family in the station. The kitchen wing was demolished when the station was moved off of railway property. Most type “E” stations had the bunkhouse converted to a baggage/express/freight shed. It is believed that Argo never had a permanent agent and that the Section Foreman’s family occupied the living quarters. Normally the Section Foreman would be provided a house separate from the station.

Museum members have been busy over the past few years restoring the interior of the station. Exterior restoration is due to be completed in 2008-09.

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