Influence of Track Maintenance on Lateral Resistance of Concrete-Tie Track

Abstract

Adequate lateral resistance is required to provide the stable track structure necessary for safe rail operations on passenger and freight railroad track. Insufficient lateral resistance, coupled with a large thermal compression force in the rail from high rail temperature, can buckle the track structure. Railroads typically use mechanical stabilization, slow orders, or both, following maintenance operations that disturb the ballast section, such as track surfacing and alignment. Tests were conducted to improve the understanding of lateral resistance variations on concretetie track caused by surfacing and subsequent stabilization or compaction. Factors influencing track stability are summarized, maintenance procedures are described, the single-tie push test is described, and test results are presented. Tests were conducted to evaluate the changes in lateral resistance, from the trafficked, well-consolidated track structure before surfacing and alignment through the laterally weak track structure after surfacing. The influence of stabilization on the lateral resistance of the track structure was evaluated. The tests results indicate that surfacing significantly reduces the lateral stability of the track to a potentially critical level. Mechanical stabilization following surfacing significantly increased the lateral stability of all sections tested.

Transverse strength of railway tracks: part 1. Planning and experimental setup

“…In consequence of ballast maintenance operations, the lateral strength can be reduced up to the 40% of its full value. Therefore, some operations cannot be carried out when the rail temperature is high, while some others are done imposing a reduced train speed until the ballast is consolidated [12]. A reliable solution to improve the track lateral stability is the adoption of sleeper anchors; unfortunately they involve additional costs.…”

“…It lays down precise limits to the CWR construction: curves having radius less than a given threshold value cannot be made by the continuous rail. Several studies have been carried out on the contributions brought to the lateral strength by the geometrical details of the track [3,6,12]. Most of them do not cover all the aspects involved: very often the scheduled experimental activities were not finished [6].…”

Analytical model for predicting the buckling load of continuous welded rail tracks

“…The pass of running vehicles tends to increase the lateral resistance provided by ballast, as ballast gets more and more consolidated. However, the value of the ballast lateral resistance is affected by the track maintenance operations that involve ballast, such as tamping or lining [16]. These operations can result in a 50% to 70% loss of the lateral resistance existing in a consolidated track ( fig.…”

“…In order to raise the safety of the track against instability, operations like the ones mentioned above are usually combined with dynamic stabilization. Dynamic stabilization of the track may restore up to 80% of the resistance lost due to tamping operations [16].…”

Transverse strength of railway tracks: part 3. Multiple scenarios test field

“…Therefore, owing to the excessive number of samples to be designed, prepared and tested, the experimental evaluation of the contribution related to each one of these parameters in scenarios which are different among them just for one parameter value becomes practically prohibitive. Several Institutions have conducted studies regarding the contribution to the resistance provided by the geometric parameters of the track and their evaluation [1,[4][5][6]. Unfortunately, the great part of these studies is incomplete: frequently, the experimental program wasn't completed [1] or some variables have been estimated rather than measured.…”