Parry People Movers
The Parry People Mover (PPM) is an innovative design of low-energy consumption railcar or tram. A testbed vehicle was demonstrated on the FR and WHR(C) in 1997 and 1998 respectively, as shown at Minffordd on the FR in this external link.
For most of 1999, the WHR(C) hosted PPM Number 11, built in 1998 and the prototype of a fleet intended for a proposed new line at Llandudno. It had a capacity of 30 passsengers seated and standing. It eventually received HMRI approval for passenger use and was used briefly in service at the very end of the 1999 season. Unfortunately, it suffered a mechanical breakdown and was sent back to the manufacturer, never to return to the WHR. In this external link it is shown outside the Dinas carriage shed.
The PPM is powered by a large flywheel underneath the floor, accelerated at intervals by an external power source. On lines designed for these vehicles, electrical power is supplied at stations, enabling the PPM to run between charges on flywheel power alone. On other lines, the PPM is fitted with a low-horsepower LPG engine which charges the flywheel as required.
Futher details can be found at Ben Fisher's WHR site and at the external Parry web page.