Concrete sleepers for secondary routes. Designs of somewhat lower strength and first cost than conventional main line sleepers (TM-CES-009)

Over the past 10 years or so, the majority of concrete sleepers purchased by BR, have been of type F27. This sleeper has a "design rail reaction" of 25 tons (250 kN) and is prestressed with 22 indented wires of 4.5Ø: The nett weight of the prestressing steel is 6,88...