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HAS is an advanced sleepered track solution designed to significantly attenuate vibration in metro environments. Developed by Alstom and Sateba (Consolis Group), HAS is composed of a heavy monoblock concrete sleeper on resilient pads placed in a rigid boot.

HAS is designed to reach high performances in terms of attenuation of ground-borne noise and vibration generated by the wheel/rail interface. It can be installed in sections of an urban lines requiring special care with regard to noise and vibrations disturbance as an alternative to floating slab tracks.

A quiet track for London

HAS is currently under installation on the Crossrail project, in London (UK), with around 5,000 HAS sleepers being laid in sensitive areas (representing approximately 3,000 single track linear metres). The line, crossing London East to West, will enter in revenue service in 2018 under the name of “Elizabeth line”.

Seamless track construction

HAS can be installed along with traditional sleepered tracks at the same construction rate and with the same equipment and workforce. On average, sleepered tracks allow construction rates 5 to 10 times higher than floating slab tracks on bearings.

Facilitated maintenance

Thanks to the easy access to the sleeper, HAS is replaceable within an overnight possession, avoiding daytime passenger traffic disruptions.

Reduced costs

HAS solution allows the track to be more compact than a floating slab track system. It optimises the civil works, such as the reduction of tunnel diameters (by around 30 cm), and thereby generates further savings.

High attenuation performance

HAS offers an attenuation higher than 20 dB, a performance equivalent to floating slab tracks. HAS is compliant with typical metro specification performance requirements.

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