Railroad Construction

Before starting railway construction various operations and activities involved in the survey of a new railway line include geological, soil-science, hydrological and other investigations.

The first essential is a thorough traffic survey. Much attention is paid to the investigation of the area, position of the new line, its construction, provisional railroad operation, observation of rives behaviour during freezing-over and drifting of ice, flood and high water.

The problems of gradients and train loads are also very important. They depend on the configuration of the broken or flat country and the volume of traffic to be carried.

The topographical maps show the planimetry and drainage of the area through which the future railway will pass. After studying maps and getting a general idea of the country, the experienced survey engineer chooses promising passes in mountain ridges to assess the feasibility of the various possible routes to be investigated. It is here that aerial photography is so useful.

The next step is to ascertain with the aid of barometric levels the altitudes of the saddles which more than anything else determine the best routes in mountainous country. The surveyor also ascertains the points along valleys to record their natural gradients as well as the points at stream confluences and beside lakes. Notes are also made on the various kinds of terrain, material to be excavated and other features of the area. Then the preliminary survey begins along the chosen route.

The preliminary survey work is especially important in really difficult country. It is based on trace of levels along the selected route. No curves are used. Levels are noted at all pegs which are checked one against another. In this way the trace can be plotted without any error. Survey in easy country is more stereotyped and depends mainly upon local and other traffic requirements, towns, villages, buildings, rivers and other country features.

Railroad building is organized at the long length grounds in deserting areas. The preliminary work involves pegging out, fixing and securing the line in the country, cleaning the right-of-way by cutting trees and rooting out stumps, draining the area and excavating the quarry for extraction of building materials.

Having done the preliminary works, the builders are engaged with subgrade and culverts construction. The next step is to lay the track and provide ballasting, build houses and structures. Special attention is given to the railroad construction under the permafrost conditions and in deserts. Snow and sand drifts challenge designers and builders and make them change and correct the standard solutions of drainage system problems.

To keep the railroad in good operation and meet the standard requirements of safety and regular trains running, the railway authorities formed a special system responsible for maintenance and repair. The railroad repair is classified as following: according to seasons, that is spring, summer and winter repair, according to volume of work, that is capital repair and running repair. Capital repair involves the entire relaying of rails and ties, selective relaying of rails and ties, replacement of switches, laying the track on the ballast and doing away with high-flood water. Running repair involves single replacement of fastenings, local track broaching, doing away with track settlement, single rail relaying and replacement ties and beams, track lining, water discharging, cleaning the track from snow, changing the signalling equipment, forcing the choked culverts.

A track measuring car is used for providing the safe running of trains. It examines the width of the gauge, the level of track settlement and the height difference between the rails.