Profile: PHW Inc. is a supplier of products for railroad and mass transit applications. We specialize in the area of fail-safe cab electronics. We are an ISO 9001 certified company. Our products are used in ensuring safe, reliable transportation on many of the busiest railroads and mass transit systems. Our product line includes continuous cab signal, intermittent cab signal, operator displays, cab signal accessories and vehicle equipment. Continuous cab signal systems receive steady streams of signal aspect information from modulated carriers in the rails. This data is continually scrutinized by a safety-critical onboard computer that determines over speed conditions and issues appropriate alerts and penalties. Aspect display unit is the primary visual interface between the vehicle operator and the cab signal system.