distance of approximately . Westbound trains from both companies used the Southern Pacific's Overland Route, and eastbound trains used the Western Pacific's Feather River Route (now called the Central Corridor). Crossovers were constructed where the lines ran in close proximity to allow reverse movements. This was necessary as while for most of this run the tracks straddle opposite sides of the Humboldt River, at points the two tracks are several miles apart and some destinations and branch lines can only be accessed from one of the lines. There is a grade separated crossover of the two lines in the shared track area near Palisade, Nevada, which results in trains following right hand traffic in the eastern half of the shared track area, but left hand traffic in the western half. The Union Pacific Railroad has since acquired both of these lines, and continues to operate them as separate lines using directional running. Amtrak also runs the California Zephyr along these routes. A similar example exists in the Fraser Canyon in British Columbia, where Canadian National and Canadian Pacific each own a single track line – often on either side of the river. The companies have a joint arrangement where they share resources and operate the canyon as a double track line between meeting points near Mission and Ashcroft. In other cases, where the shared lines already run in close proximity, the two companies may share facilities. In Conshohocken, Pennsylvania, where the former Reading Railroad and Pennsylvania Railroad shared lines, the lines even shared overhead electrical wire supports, for a stretch on the northern bank of the Schuylkill River. Both lines eventually came under Conrail ownership in 1976, with the former PRR line being abandoned and now used as a hiking and bicycle path. An unusual example used to exist on the Isle of Wight, where until 1926 parallel tracks between Smallbrook Junction and St John's Road existed. The Southern Railway installed the actual junction, but it was only used during heavily trafficked summer months. During the winter, the lines reverted to separate single-track routes. Mixing double and single track Because double and single track may use different signalling systems, it may be awkward and confusing to mix double and single track too often. For example, intermediate mechanical signal boxes on a double-track line can be closed during periods of light traffic, but this cannot be done if there is a