Test Results of a Modified Turnout Designed to Increase Diverging Route Speeds Without Increasing Lead Length

This paper presents the results of Phase II of a Federal Railroad Administration sponsored study looking at low-cost means to increase speeds through turnouts by retrofit or upgrade. To meet this objective, lead length and frog angle were considered fixed, eliminating the costs to relocate the frog or switch points. Based on extensive research, it was determined in Phase I that the best solution was to optimize the existing AREMA geometry by reducing the switch angle, incorporating a new diverging switch rail, and reshaping both the curved stock and closure rails. Dynamic simulations showed that higher speeds could be achieved over the optimized geometry without increasing peak wheel/rail forces experienced over the traditional geometry. In Phase II the new design was tested by retrofitting an AREMA #20 crossover on New Jersey Transit. Full testing of the crossover included comparison with a standard AREMA #20 based on lateral and vertical wheel/rail forces and lateral car body accelerations. From current observations and test results, the new turnout design meets the goal of providing a low-cost means to increase the speeds through existing turnouts. By establishing a superior geometry within the same dimensions as the AREMA standard, railroads will be able to make the necessary modifications at low cost and without the need of additional space. In addition, this approach, applicable to the large majority of existing turnouts, is expected to result in improved ride quality and decreased wear, leading to a longer service life and decreased maintenance costs