A railway zig zag or switchback, is a method of climbing steep gradients with minimal need for tunnels and heavy earthworks.For a short distance (corresponding to the middle leg of the letter "Z"), the direction of travel is reversed, before the original direction is resumed. Not all switchbacks come in pairs, in which case the train may need to travel backwards for a considerable distance.
A location on railways constructed by using a zig-zag alignment at which trains have to reverse direction in order to continue is a reversing station.
One of the best examples is the Darjeeling Himalayan Railway, a UNESCO World Heritage site railway in India, that has six full zig zags and three spirals.
Zig zags tend to be cheaper to construct because the grades required are discontinuous. Civil engineers can generally find a series of shorter segments going back and forth up the side of a hill more easily and with less grading than they can a continuous grade which has to contend with the larger scale geography of the hills to be surmounted.
Zig zags suffer from a number of limitations:
If the wagons in a freight train are marshalled poorly, with a light vehicle located between heavier ones (particularly with buffer couplings), the move on the middle road of a zig zag can cause derailment of the light wagon.
The Cascade Tunnel refers to two railroad tunnels in the northwest United States, east of the Seattle metropolitan area in the Cascade Range of Washington, at Stevens Pass. It is approximately 65 miles (105 km) east of Everett, with both portals adjacent to U.S. Route 2. Both single-track tunnels were constructed by the Great Northern Railway.
Lithgow is a city in the Central Tablelands of New South Wales, Australia and is the administrative centre of the City of Lithgow local government area. It is located in a mountain valley named Lithgow's Valley by John Oxley in honour of William Lithgow, the first Auditor-General of New South Wales.
Glenbrook is a suburb of the Lower Blue Mountains of New South Wales, Australia. It is located 70 kilometres west of Sydney in the local government area of the City of Blue Mountains. At the 2016 Australian census Glenbrook had a population of 5,051 people.
A spiral is a technique employed by railways to ascend steep hills.
The Zig Zag Railway is an Australian heritage railway, situated near the town of Lithgow in the state of New South Wales. The line climbs the western flank of the Blue Mountains, using railway zig zags to gain height. It was opened by the not for profit Zig Zag Railway Co-op. Ltd. as an unpaid volunteer staffed heritage railway in October 1975, using the alignment of the Lithgow Zig Zag line that formed part of the Main Western line between 1869 and 1910.
Hillclimbing is a problem faced by railway systems when a load must be carried up an incline. While railways have a great ability to haul very heavy loads, this advantage is only significant when the tracks are fairly level. As soon as the gradients increase, the tonnage that can be hauled is greatly diminished.
A gravity railroad or gravity railway is a railroad on a slope that allows cars carrying minerals or passengers to coast down the slope by the force of gravity alone. The speed of the cars is controlled by a braking mechanism on one or more cars on the train. The cars are then hauled back up the slope using animal power or a stationary engine and a cable, a chain or one or more wide, flat iron bands. A much later example in California used 4 ft 8 1⁄2 instandard gauge steam engines to pull gravity cars back to the summit of Mt. Tamalpais.
Lapstone is a suburb on the eastern escarpment of the Blue Mountains in New South Wales, Australia. Elevation 160m. Lapstone is located 62 kilometres west of the Sydney CBD in the local government area of the City of Blue Mountains and is part of the federal electorate of Macquarie. Lapstone consists mostly of stand-alone housing and has a few public facilities. At the 2016 census, Lapstone had a population of 961 people. Lapstone was originally bought and developed by Mr Arthur J Hand, an Alderman of the Blue Mountains City Council.
The Lapstone Zig Zag was a zig zag railway built near Lapstone on the Main Western line of New South Wales in Australia between 1863 and 1865, to overcome an otherwise insurmountable climb up the eastern side of the Blue Mountains.
The Blue Mountains Line (BMT) is an inter urban rail service operated by NSW TrainLink serving the Blue Mountains region of New South Wales, Australia. The line travels west from Sydney to the major town of Katoomba and on to Mount Victoria, Lithgow and Bathurst. Mount Victoria is the terminus for most electric services, but some services terminate at Lithgow instead. 2 Express services per day in each direction, known as the Bathurst Bullet, extend to the regional city of Bathurst, which is supplemented by road coaches connecting Bathurst to Lithgow. Due to electrification limits at Lithgow, the Bathurst Bullet is run using the Endeavour railcars, which operate on diesel. The Blue Mountains Line operates over a mostly duplicated section of the Main Western line. As such, the tracks are also traversed by the Central West XPT, Outback Xplorer and Indian Pacific passenger services and by freight trains.
Zig Zag railway station is located on the Main Western line in New South Wales, Australia. It exists to serve the Zig Zag Railway to the east of Lithgow. A station opened on the site on 15 April 1878, closing on 16 October 1910 when the Ten Tunnels Deviation opened. A new station opened on the site in 1959. Since December 2019, this station has been closed until further notice due to repairs from bushfire damage.
The Main Western Railway is a major railway in New South Wales, Australia. It runs through the Blue Mountains, Central West, North West Slopes and the Far West regions.
The Lithgow Zig Zag is a heritage-listed former zig zag railway line built near Lithgow on the Great Western Line of New South Wales in Australia. The zig zag line operated between 1869 and 1910, to overcome an otherwise insurmountable climb and descent on the western side of the Blue Mountains. It was designed by John Whitton and built from 1863 to 1869 by Patrick Higgins as contractor. It is also known as the Great Zig Zag Railway and Reserves and Zig Zag Railway. The property is owned by Department of Planning and Infrastructure. It was added to the New South Wales State Heritage Register on 2 April 1999.
The Dargans Deviation was a section of the original line over the Blue Mountains in New South Wales, Australia. It was constructed from 1896 to 1897 in an effort to ease the grades of the original alignment from before Newnes Junction to Clarence, with a ruling grade of 1 in 60. Along with a few crossing loops, it enabled much longer trains to use the line. After the construction of the Ten Tunnels Deviation, it was abandoned.
The Glenbrook Tunnel is a heritage-listed single-track former railway tunnel and mustard gas storage facility and now mushroom farm located on the former Main Western Line at the Great Western Highway, Glenbrook, in the City of Blue Mountains local government area of New South Wales, Australia. It was designed by Department of Railways and built from 1891 to 1892 by Department of Railways. It is also known as Lapstone Hill tunnel and Former Glenbrook Railway and World War Two Mustard Gas Storage Tunnel. The property is owned by Blue Mountains City Council and Land and Property Management Authority, an agency of the Government of New South Wales. It was added to the New South Wales State Heritage Register on 5 August 2011. The railway tunnel was originally part of the 1892 single-track deviation, which bypassed the Lapstone Zig Zag across the Blue Mountains. It is 634 metres; 693 yards long and is constructed in an 'S' shape with a gradient of 1:33.
The Ten Tunnels Deviation is a heritage-listed 9.2-kilometre (5.7 mi) section of the Main Western Line between Newnes Junction and Zig Zag stations in Lithgow, New South Wales, Australia. It was designed and built by the New South Wales Government Railways and built from 1 June 1908 and 16 October 1910. It is also known as Great Zig Zag Railway deviation tunnels and Bell to Zig Zag Ten Tunnel Railway Deviation. It was added to the New South Wales State Heritage Register on 2 April 1999.
The Lichte (Thuringia) station German: Bahnhof Lichte (Thüringen) was a Deutsche Reichsbahn station in the Thuringian municipality of Lichte in the district of Saalfeld-Rudolstadt. The station is elevated 623 m above Sea Level.
The Kieselbach is a right tributary of the Lichte in Thuringia, Germany, and is 4 km (2.5 mi) long.
Flieden station is a station in the town of Flieden in the German state of Hesse, where the Flieden–Gemünden railway branches off the Kinzig Valley Railway. The station is classified by Deutsche Bahn (DB) as a category 5 station.
Bottom Points is a railway station on the Zig Zag Railway in the Blue Mountains area of New South Wales.
High mountain levels … may be tunneled … but … may be reached by one of several methods adopted to secure practical grades: (1) Zig-zag development … (2) Switchback development … (3) Spirals or loops …