The design issue under consideration includes route surveying, track component identification, designing the rail curve and other design aspects that help in improving rail transport. Suggestion indicated can be implemented by any train organization seeking to improve or optimize there services (Mundrey, 1993).
Rail tracks are used for the guidance of trains, and consist of two steel rails laid in parallel. The rails guide the train in motion without the need for steering. The rails are laid on sleepers. The sleeper are also referred to as the cross ties. The sleepers are embedded in the ballast and form the rail road track. The rails are fastened to the sleeper by the use of spikes, lag screws, bolts clips and pandrol clips. The type of fastening sleepers depends on the type of sleepers. For the concrete sleepers clips are used, for the wooden sleepers' spikes are used and for steel sleepers, bolts are commonly used.
Convectional rail design involved route surveying and finding the most economical route for the rail line. The engineer worked on ways of designing the rail so as to surpass the geographical obstacles (Engineering Policy Group (EPG). 2009).
Currently rail design encompasses many design aspects. These design aspect results from the need for greater speeds and heavy loads. Due to these factors, the most important consideration for the rail design are:
Route surveying. This involves planning the rail routes so that it passes through the most economical route (Hickerson, 1967).
Long term traffic levels; if the projection shows that in the long run the traffic will increase. Design consideration for expansion of the rail as well as incorporating trains with high speed and heavy should be taken into consideration.
Environmental concern: the design should focus on an environmental friendly rail that does not damage the environment.
Politics: Government influences and funding greatly affect the quality of the rail and also its long term benefits.
Land issues; when designing for increased speed, huge curves are required; the constraining factor to this is the limitation of land.
Economic factors: this determines the type of rail constructed. Well funded projects can archive most of the design requirements.
Design of The track bed
The rails are laid on a bed of stones, ballast is commonly used. The bed is comprised of the following major layers;
The subsoil: this is the natural ground in which the rail is to be laid.
The sub grade: this comprises of compacted soil. The compaction and removal of clay from this layer prevents the expansion and compression preventing the sinking of the rail which damages this track. The soils used in this layer must not expand or compress due to water absorption. Compression of the soil also helps is preventing the infiltration of water and clay.
Blanket: this is a layer of stone dust or sand, it is mixed with impervious plastic. The layer prevents the upward infiltration of clay and water which may destroy the rails.
Ballast: This is a layer of stone. The type of stone used and the grade of the ballast determine its load bearing