http://www.engineeringnews.co.za/articl ... 2011-04-08
Precast concrete structures provide railway infrastructure solutions
By: Henry Lazenby
8th April 2011
Precast concrete manufacturer Rocla says it has seen significant demand for its newly developed security housings for trackside railway signalling equipment.
The company developed the reinforced concrete structures as railway signalling equipment is increasingly being targeted by criminals who steal the valuable electronic components found inside the signalling boxes. The product was gradually introduced to the market during last year.
Rocla marketing director Craig Waterson says that signalling equipment is critical for the safe operation of railways, especially the busy suburban commuter lines in Gauteng and the Western Cape.
“Thieves have identified the contents of signalling houses as lucrative targets. Owing to this, we have come up with a solution to better protect signalling equipment,†he says.
The solution is to replace the traditional brick and mortar buildings, housing the signalling equipment, with reinforced concrete structures that cannot be easily broken down using hand tools.
Rocla reports there has been significant interest from the railway industry, with a number of these units installed along Gauteng’s commuter railway lines at locations where signalling equipment has been stolen a number of times.
Waterson says the concrete enclosing is cast in one piece, with the security door also cast into the structure. The structure can withstand up to 50 MPa of pressure.
Further, the companylaunched its new range of concrete overhead electric wire catenary masts at the end of last year. Although the product is not new to the South African market, it is a new offering from the company.
Waterson explains that concrete catenary masts are much more durable than the traditional steel catenary masts, and have a longer life span. “Concrete masts are rapidly replacing steel masts along coastal railways, as these are more durable and virtually maintenance free,†he says.
Further, he points to an international trend where head and wing walls, used at both ends of pipe culverts installed through fill embankments, are now precast. Waterson says these structures were traditionally cast on site but it is now the preferred practice to use precast structures, owing to the increased quality controls that the precast method offers. For this application, Rocla introduced a new local product.
Concrete Infrastructure
Rocla is currently providing precast culverts and stormwater drainage pipes for an extension of the Sishen – Saldanha iron-ore line. The extension forms part of the iron-ore export channel expansion programme.
Mining company Kumba Iron Ore and transport parastatal Transnet announced plans in 2008 to further upgrade and expand the Sishen–Saldanha ore export channel to 60-million tons a year, with nine-million tons a year of the additional capacity to be allocated to Kumba for its new Kolomela mine, near Postmasburg.
Waterson reports the company has supplied a significant number of precast concrete culverts for the project.
“Constructing railway lines often entails providing for stormwater drainage systems under the line as well as access points from one side to the other for people and livestock. Rocla has been involved with the Sishen–Saldanha line from the start, including all the extensions since the line was first built about 35 years ago,†he says.
Further, with the company’s products being South African Bureau of Standards approved, Waterson adds that contractors know that the company’s products are manufactured to high quality standards.
Meanwhile, he believes railway development in Southern Africa has been somewhat neglected in the past, resulting in the area losing out on the potential benefits offered by the previous commodity boom, owing to inadequate transport solutions being available.
He is, however, optimistic about the medium-term outlook as the company is currently quoting on a number of substantial tenders for railway development in Africa.
The most significant project is the Tete–Nacala coal export railway, in Mozambique, which will be between 700 km and 1 000 km long, and which is being built by the Mozambican government.
Rocla’s primary focus is on manufacturing precast concrete structures for use in infrastructure developments.
Waterson says the company has an engineering team that works with its clients to develop specific solutions for challenges they may have to deal with. “Service delivery is always part of our focus, ena- bling us to get the required products to the contractors at the prescribed times, so as not to delay contracts.
“With our large geographic footprint of 13 factories in Southern Africa, including one in Botswana and one in Namibia, we are able to efficiently provide infrastructure components to railway line construction,†he concludes.
Edited by: Chanel de Bruyn