As part of the Next Generation High Speed Rail Program, two types of concrete slab track were tested to determine their ability to retain the exacting track geometry tolerances required for high speed rail operations while also withstanding the high axle loads of main line freight service. These two designs were proposed options for locations where future high speed passenger service may need to share track with heavy freight service, particularly in urban areas where available rights-of-way are limited and where access for maintenance may be difficult. The test and demonstration was conducted at the Transportation Technology Center (TTC) near Pueblo, CO, from July 2003 to July 2006, as a cooperative effort between the Federal Railroad Administration (FRA) and the Portland Cement Association (PCA). The demonstration section was 500 feet long, with 250 feet of direct fixation slab track (DFST) and 250 feet of independent dual block track (IDBT). During the test and demonstration, a train with 39-ton axle loads was run repeatedly over the two concrete slab track sections. Over 3 years, a total of 170 million gross tons (MGT) of traffic was accumulated. Various measurements taken during and at the end of the demonstration indicated that FRA Class-9 track geometry tolerances (the highest track class, for speeds up to 200 mph) were successfully retained. In addition, no signs of structural distress appeared.

Travel through the diverging route of a turnout can produce high lateral forces and accelerations, particularly in the areas of the switch point and frog. These higher lateral forces and accelerations require slower operating speeds and have adverse effects on ride quality and component life. This study was aimed at finding a low-cost means to reduce lateral forces and accelerations so that safe speeds through turnouts could be increased. Meeting this objective required that the key turnout dimensions of lead length and frog angle be kept fixed so that no track reconfiguration would be needed and the new design could fit within the existing turnout space. The objective was achieved by reducing the switch angle in the conventional American Railway Engineering and Maintenance of Way Association (AREMA) turnout, along with lengthening the switch points and reshaping and shortening the curved closure. When applied to a No. 20 turnout (Figure 2), dynamic simulations and field measurements showed that this design would allow diverging speeds to be increased from the current limit of 45 mph to 55 mph without producing peak wheel/rail forces and lateral accelerations, which exceed those produced with traditional turnout geometry.