Rail Track Design Issues - Essay Example

The safety and efficiency in the operation of rail transport systems are dependent basically on a good rail track design. The rail track should be designed and laid out to ensure that practical freights and convenient travel time are attainable. The roadways should be provided with sufficient clearances, suitable cants, and practical radii on curves. The components of the rail track must be selected prudently to enhance safety and security in railroad facilities. Proper selection of rail track components also reduces the necessity for frequent maintenance.

Route surveying is done to acquire necessary data for the proper placement of grades, bridges, culverts, and curves in a railroad system. The usual route surveying can be done traditionally or electronically. Traditional route surveys employ ‘differential levelling, taping manually scribed data, cross sections and baseline-referenced topography’. Electronic surveys, on the other hand, make use of ‘total station, data collector and computer technologies’ for field data acquisition and manipulation (Engineering Policy Group, “Route Surveying”, par. 1, 2).

The Swiss Trolley, ‘a multi-sensor measurement system incorporating real-time kinematic (RTK) GPS’ has been used in the United Kingdom for precise and accurate rail track surveying. This rail track surveying system is essential in the redesign and renewal of railroads because it provides ‘dense and accurate track information’ which assures a ‘precise description of the actual physical track’ (Glaus et al, par. 1).

The rail track supports the train weight, tractive and braking forces, and lateral forces from guiding the wheels. Thus it is vital to choose and use rail components that are ‘suitable for the proposed duty and fit the purpose’. Rail size must be selected correctly (see Figure 2), and methods of joining rails can either be Thermit (aluminium oxide) welding or ‘huck’ bolts together with standard fishplates. Rail-to-sleeper fastenings must provide resistance to the ‘overturning force on the rail and lateral steering forces on curves’ and should maintain gauges. In the United Kingdom, ‘surface mainline tracks usually make use of tapered baseplates (Figures 3 & 4) to counteract these resistances (HSE, p. 5, 11, pars. 1).

To guarantee a superior quality track, proper ballasting is crucial. According to HSE (p. 14) ballast installed in rail tracks must fulfil the following purposes:
- Transferring the load to the roadway floor;
- Holding the sleepers in place;
- Allowing water to drain; and
- Permitting the regarding of track.

It is essential for ballast to ‘not crumble under load or wet conditions’ and ‘should bind together as a mass when laid, but ought to retain its open structure to allow drainage’. Usually, the ballast size used is 28 mm single-sized for high-speed tracks. Granite ballast is resistant to wear and tear and thus provides durable rail track ballast (HSE, p. 15).