Back on the rails18 September 2012
Mitchell has plans for crawlers that ride the rails, as other manufacturers Kirow, XCMG, Tadano Mantis, Sennebogen and Kirovsky improve their railway cranes. Cristina Brooks reports
World Bank statistics show that the world's longest railway tracks are in India, South Africa, and China. France and Canada are also major investors in the sector. These tracks are growing as well, creating a market for construction railway cranes.
Public and private contractors use railway cranes to build and repair tracks, and also construct hard-to-access railway overpasses/bridges, tunnels, electrical wires, and stations. Some heavier models are used to rescue derailed railcars.
With long life cycles, production numbers for railway cranes can number in the single digits, so technological development is slow.
Traditional heavy-duty, track-bound railway cranes are designed to lift at long radius. Kirow's 1680t railway crane can lift 160t at 10.5m.
Avoiding blocking tracks is a vital issue for railway-line customers. Many cranes slew 360° and some do so with a non-slewing counterweight.
As well as reducing space taken by counterweight, locomotive crane designers have sought to allow cranes to leave the tracks, clearing the way for trains to pass.
There are two primary types of road-rail cranes: truck versions have rubber tyres that are locked on the rails and can only leave the rails at crossings, while hi-rail friction drives allow rail wheels to retract, and tyres set down, to take the crane off the tracks anywhere.
Road rail-cranes offer an attractive alternative to road-transported cranes for remote construction work. "Sometimes where they have to go is not anywhere close to a town.
It's way, way away from any roads that would be accessible," says road-rail gear producer, Mitchell Railgear's managing director, Estel Lovitt.
Crawlers could ride rails
Sennebogen's 8t wheeled mobile telescopic crane, the 608 Multicrane, can be fitted with forks, winches and other attachments. It has been adapted for use on rails, using a hydraulically retractable rail undercarriage.
German client Himmel & Papesch Bauunternehmung, for example, has used the 608 Multicrane, fitted with a working platform and drill, to secure embankments alongside railway lines.
While Sennebogen has seen demand for these small, multipurpose machines, marketing managing Florian Attenhauser, doesn't think it will be possible to take larger crawler cranes on and off tracks: "As soon as the crawler driven machine tries to get on rail, it won't be easy to avoid damage to the railway."
The heavier crawlers Sennebogen builds would undoubtedly tear up railway tracks if they ran over them, but, for very light crawlers, a solution may be in sight.
Mitchell Rail Gear, a specialist manufacturer of road rail attachments, has come up with a solution that allows comparitively lighter (up to 90,000lb or 40t gross vehicle weight) crawler excavators to work on rails.
At the request of clients, manufacturers such as Terex and Grove have their cranes delivered directly to Mitchell as they come off production lines. Mitchell then custom designs and produces railgear for that particular crane. Truck cranes are equipped with railgear, so that the tyres drive on the rails.
Rough terrain cranes are equipped with friction drive hi-rail: the tyres drive friction hubs that are attached to the railwheels. Mitchell's Autoguide suspension system allows rough terrain cranes or crawler excavators to propel themselves on the railway sleepers (also known as ties), guided by railwheels. However, the height difference between rail and sleeper varies continuously, for example as the railway passes crossings. To maintain traction and stability, Autoguide automatically adjusts the railwheels' suspension.
Mitchell has already used its Hydra-Guide Rail Gear to allow crawler excavators to propel themselves on rails up t o 20mph. The excavators can then retract the rail gear, either to work from the tracks with crawlers down or ride off. The system links the railwheels to the excavator's hydraulic system to drive it on the track.
Lovitt says Hydra-Guide has been used on 90,000lb excavators without problems. While this is not very big for crawler cranes, it does mean that some smaller models could be fitted with the system. Lovitt points out that using crawler cranes rather than crawler excavators could add capacity and reach when lifting materials.
Lovitt says, "The system is hydraulically driven, each motor has its own built-in traction control similar to how a locomotive controls wheel slip to be able to maximise tractive effort.
"Functionally, it's similar to a friction drive but we're able to use it to equip machines that you can't friction drive. We have had a lot of interest in applying these to crawler cranes. Hydrostatic drive allows them to do the same thing they can do on friction drive.
"They can go 20mph on the tracks, with as much tractive effort as friction drive mechanical systems. It can be applied to track cranes equally to rubber tyres which gives them the ability to get off the track, and more ability to maneuver," says Lovitt.
Technologies like this could be sold globally, and particularly in countries with poor road infrastructure: recently Mitchell has seen orders from Chile and Africa.
Built for power
While Mitchell's solutions allow smaller equipment like truck cranes, rough terrains and small crawlers to get on and off tracks, big lifting jobs require purpose-built railway cranes.
The purpose-built railway crane industry has its roots in mid-19th century Europe. Intense competition has meant that few firms remain in Europe today. Major manufacturers like Gottwald and Cowans Sheldon have ceased rail crane production.
However, Kirow, based in Leipzig, Germany, still leads the market. Its general construction crane, the Multitasker can pick and carry at up to 12mph, with capacities up to 160t. Ludwig Koehne, managing director of Kranunion and Kirow says, "The load could be any kind of preassembled module on a railway, in a station or car, or yard."
Over a decade ago Kirow introduced a unique double slewing ring that keeps the counterweight from moving with the crane during construction. "It's good for contractors working in tunnels that our crane can work with horizontal booms and without moving the counterweight to the side," Koehne says.
Kirow cranes can telescope under load. Koehne says, "You need it to be able to unload heavy items from train wagons. We engineered this feature 20 years ago." This allows the crane to be used to heavy install electrical components such as transformers at switches and crossings.
Koehne says the industry is heading in the direction of bigger and more powerful cranes: "The industrial logic is quite simple: the more you can preassemble, the bigger the modules you assemble, the more productive you are because you need less time on the track. In 1997 our biggest crane was 800tm, and we have now doubled it to 1,600tm in the last 15 years."
Kirow expects market growth outside of Europe, in countries that are currently investing in infrastructure, in South East Asia, Latin America, Australia and some parts of Africa. Recently it has supplied cranes to Bangladesh and Saudi Arabia.
"I think any country with fast growing cities is well advised to invest in railways, and also countries with raw materials," says Koehne.
Chinese cranebuilder XCMG certainly sees the potential in the rail crane market. XCMG's railway cranes range from 1-16t with applications in loading and unloading railway line components from transporters, laying and repairing railway tracks. Its TSQ6.3SK2Q was developed in 2007 to expand the rail-crane market.
XCMG's major focus is its domestic market in China, where it supplies manufacturers of railway equipment. These include Xiangfan Golden Eagle Railway Vehicle and Machinery, a manufacturer of heavy-duty rail vehicles, electric railway engineering machinery and Taiyuan Railway Transportation Equipment. XCMG also supplies to Taiwan, and to Africa.
In neighbouring Russia, another rapidly growing economy, Kirovsky Mashzavod 1 Maya (Kirovsky) supplies to major railways, such as the government owned rail carrier of the Russian Federation RZD.
Through its distributors, it supplies former Soviet Union nations such as Kazakhstan, Belarus, Ukraine, Tajikistan, Armenia, the Baltic states, Turkmenistan, Uzbekistan, Iran, Libya, Cuba, Mongolia. In the last year it received large order for construction of railroads in Turkmenistan.
Founded in 1899, the company today offers traditional railway cranes with capacities up to 150t. Its cranes build railway bridges, bridges above railroad tracks, and lay railway switches. They also do material handling industrial locations equipped with railway approach lines.
Oleg Smirnov, head of marketing Kirovsky, explains running cranes on rails requires many approvals; that means customers are usually railway owners.
Kirovsky produces cranes that have a double slewing ring to prevent tailswing, but this feature is mainly for export. Smirnov says, "Abroad, cranes are mostly used for rail-laying, that is why cranes for export have a reduced tail radius, double rotary mechanism, leveling system in curves."
In recent years the company has developed a stronger boom that has allowed increased lifting capacity at longer radius. The boom had been restricted to the width of the undercarriage. By setting it off-gauge, Kirovsky could increase lifting capacity while keeping the same vehicle weight.
Kirovsky is designing a 120t capacity prototype for Egyptian National Railways and Iran Railways. The company plans to develop this into a production unit able to lift up to 250t, with a load moment exceeding 2000tm.
The company sees its future market growth coming from the Middle East, Eastern Europe and African countries, such as Iran, Egypt, Georgia, and Azerbaijan.
Tadano Mantis Corporation, formed when Tadano acquired crane builder Mantis in 2008, continues the development and production of Mantis road-rail cranes on trucks.
Mantis produced its first road-rail cranes in the 1980s. These include the rail accessible 150USt capacity 30011 Truck/Rerailer, shown on the cover.
Tadano Mantis says that North American Railroads have made increasing use of road-rail re-railing cranes and subsequently replaced their rail-bound breakdown cranes. Tadano Mantis says the 30011's ability to hop off tracks as needed cuts mobilisation times when going to accident sites. Many trains are usually backed up between the yard and the wreck. These must be shunted off the line to permit a rails-only breakdown crane to get through. This can often take as long as a day. The 30011, however, can go around the stopped trains. Once the track-based breakdown crane has finished work the same problem exists in returning to the railway station on the rails. A breakdown crane has low priority and must clear the way for oncoming trains, so this can take a week or longer.
Rerailer cranes like the 30011 are also less expensive, adding a cost advantage.
Tadano Mantis says that as well as being used for rerailing, its crane can help justify its cost from the lift crane service it performs for major rail customers who need crane service in their yards.
The 30011 has applications in installation for railway yards and lines: it can lift containers, double stacks, change wheel sets, install switches.
Tadano has introduced a 25,000lb self-erecting counterweight that ups crane capacity at extended radius and enables lifting to the side, from adjacent tracks.
Tadano Mantis has engineered the 30011 for lifting to the back as well, enabling tandem rear rail trucks for pick and carry over the rear of the crane.
Railroad contractors in places as far away as the Middle East and South Ameirca have recently purchased the 30011 and use it for construction work such as bridge building in addition to moving heavy loads like propane tanks.