In general, the grooved rail sections that are available from Europe come in two varieties – those with flangeways that are too small for North American railroad wheel flange profiles and those with flangeways that are too large to satisfy guidelines of the Americans with Disabilities Act (ADA) for walking surfaces. Use of these European rails will usually require adoption of a European type of flange profile as is currently in use on a US transit system and illustrated in Figure 7. Grooved rails are sometimes made of softer steel than common T-rails. This is because the more complex shape of the grooved rail requires more passes through the rolls compared to T-rail. The temperature of the nascent rail is reduced with each pass and if the rail steel chemistry isn’t soft enough, it may not be possible to make the last few passes without fracturing the rail. Some European suppliers can provide surface weldments to increase the durability of grooved rails, but results have been mixed. One manufacturer had just recently begun offering a heat treatment process for grooved rails, but the product has not been on the market long enough to be considered proven. Most North American LRT projects have used T-rail for paved track installations, usually because railroad flange profiles were adopted. Methods for providing the requisite flangeway have varied, as have results. Similarly, methods and results for providing a guard rail in curves have varied by project. One method consists of a vertically mounted restraining rail that is bolted to the running rail every two to three feet. A few projects have used a special rolled shape – strap guard – that mates with common 115RE T-rail and provides a flangeway that mimics that once provided by North American girder guard rails as is shown in Figure 5. Guideline – If grooved rail is used, then a wheel flange profile optimized for the girder guard rail should be adopted. Both the gauge and guard side flange angles from vertical and the tip radii on both the running rail and guard side of the flange should be analyzed for use on curve radii below 15 meters (49 feet) and adjusted for perfect compatibility if found necessary. Alternatively, a flange profile in use on a European property with curve radii equal to that to be used on the Light Rail Circulator System can be adopted. The flange should include the typical flat tip that works best with flange-bearing frogs, crossings, and switch point mates. (See Figure 7.) Such flanges are used at speeds of up to 100 km/h (62 mph) in Europe, so pose no constraints on system expansion. If grooved rail is used, attention should be given to its carbon content to ensure procurement of rail that is no softer than is necessary. 5.3 Use of Bolted Connections Light Rail Circulator System track embedded in concrete is not very maintenance-friendly.
