The current Network Rail UK protection systems are TPWS and AWS. The functionality of both systems is combined in a single system, generally referred to as TPWS. TPWS comprises of OSS (Overspeed Sensor System) and TSS (Train Stop System).

The OSS system automatically applies the vehicles emergency brakes when the vehicle exceeds the posted speed over an active OSS transmitter. The TSS system automatically applies the vehicles emergency brakes when the vehicle passes an active TSS transmitter installed at stop signal. AWS gives train drivers an audible and visual indication of the status of the signal ahead. If the driver does not acknowledge the indication of a caution signal the AWS system automatically applies the vehicles emergency brakes.

Mors Smitt TPWS system is based around a TPWS Control Unit to which all other AWS and TPWS equipment is connected. For simplification however, the complete train borne TPWS system can be split into four distinct elements, these being the Control Unit, AWS Receiver, TPWS Antenna and Cab Controls and Indicators. Included Specific Transmission Module (STM) is aimed to manage the interface between existing national train protection systems and ETCS to provide continuous train operation on sections not covered by ETCS.

Mors Smitt TPWS is ready for both Isolated Speed Limited Authority (ISLA) and Radio Based Limited Supervision (RBLS). Isolated Speed Limited Authority (ISLA) is a future TPWS development which will provide:

• Line speed supervision
• Temporary Speed Restriction (TSR) and Emergency Speed Restriction (ESR) remote deployment and supervision
• Possession boundary control/supervision
• Controlled/supervised moves through possessions
• User Worked Crossing safety enhancements

Radio Based Limited Supervision (RBLS) is a future development based on core principles of ETCS and TPWS to provide:

• Signal aspect supervision
• Continuous supervision benefits at a fraction of the cost of ETCS
• Relatively quick and low-cost vehicle installation compared to ETCS
• Minimal driver training required, as based on familiar TPWS control panel

Download:

TPWS and AWS Flyer