According to A. Bray Dickinson the North Shore (North Pacific Coast) had 2 tunnels with the distinction of having 4 rail track run through them. These were the Corte Madera Tunnel and the White's Hill Tunnel. The 4th rail was for electrical transport for the standard gauge interurbans. They were in use from about 1903 to 1920 when the narrow gauge was cut back to Point Reyes Station.