Glenbrook Tunnel (1913)

At , the 1913 tunnel was shorter than the 1892 Glenbrook Tunnel. However, the 1913 deviation was approximately longer than the 1892 deviation. The 1913 deviation did not improve the time taken to climb or descend the pass between Emu Plains and Blaxland stations, however a reduction in gradient from 1:30 to 1:60 made the pass more manageable and reduced challenges with steam locomotives in tunnels on significant gradients, including reducing the possibility of suffocation. When the deviation opened in May 1913, the single-track 1892 tunnel, with a gradient of 1:30, was used for east-bound trains and the new 1913 tunnel, with a gradient of 1:60, was used for west-bound trains. After the new line duplication was completed on 25 September 1913, the old (1892) Glenbrook Tunnel was no longer used for trains and the old Glenbrook station was closed. Steel sleepers were used instead of traditional wooden sleepers. Electricity supplied power to the tunnel for lighting and electric fans used to maintain air quality. == Slab track ==

The track through this tunnel was eventually converted to so-called Slab track whereby the ballast was replaced by a concrete slab. This would have improved clearances inside the tunnel. But slab track created a new problems, namely that the slab track was stiffer than the ballasted track that adjoined it, and a transition was needed between the two stiffness levels. The transition was implemented by installing two extra "check rails" extending, say, 20m into the tunnel and 20m along the ballasted track. This created its own problem in that the last 20m of ballasted track was difficult to tamp because of the extra rails. == See also ==