Parry People Movers
Encyclopedia
Parry People Movers Ltd. (PPM) is a British
company manufacturing lightweight tram
s and railcar
s that use flywheel energy storage
(FES) to store energy for traction, allowing electric systems to operate without overhead wires or third rails, and railcars fuelled by small gas, diesel or hydrogen engines, offering very high energy efficiency and very low emissions, suitable for new-build or existing rail systems in a variety of gauges, serving both urban and rural communities in any part of the world.
, owner of the West Midlands franchise, began operating a single PPM50 (Class 999) unit on the Stourbridge line on Sundays in 2002, with a Class 153 Diesel multiple unit
(DMU) providing a weekday service. In June 2009, the Class 153 was replaced by two PPM60 units, classified as Class 139
(with another as spare), providing a 10-minute frequency in both directions. Although the capacity of the unit (60 passengers) is less than the DMU, overall capacity is increased due to the greater frequency, up from 4 to 6 trains per hour.
From 24 January 2011, Go! Cooperative
planned to be operating a trial service between Alton
and Medstead & Four Marks
on the Mid-Hants Railway using the Class 999 unit. Due to technical issues however, this has been delayed until November 2011.
The Parry flywheel storage technology was tested on the Stourbridge Town Branch Line
in the West Midlands
in 2006. Since Central Trains
had no Sunday service on the branch, the initiative was brought to test a PPM50 model at that time, with a view to replacing the Class 153
single-car Diesel Multiple Unit
that previously worked the Branch with a unit with much lower operating costs. The trial lasted for a year.
Parry People Movers have also been demonstrated on narrow gauge railways (Welshpool and Llanfair Light Railway
, Ffestiniog Railway
, Welsh Highland Railway
).
s, approximately 1 m in diameter and 500 kg in mass, designed to rotate at a maximum speed of 2,500 rpm. The flywheel is mounted horizontally at the centre of the unit, beneath the seating area.
The flywheel
allows the direct capture of brake energy (when slowing down or descending gradients) and its re-use for acceleration. Since the short-term power demand for acceleration is provided by the energy stored in the flywheel, there is no need for a large engine. A variety of small engine types can be used including LPG, diesel
or electric traction.
On a route with stations a short distance apart it is theoretically possible to use the unit as a tram
without any engine or overhead electrification at all. Instead the flywheel could be re-energised at each station storing enough power to carry it on to the next.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
company manufacturing lightweight tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...
s and railcar
Railcar
A railcar, in British English and Australian English, is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach , with a driver's cab at one or both ends. Some railways, e.g., the Great Western...
s that use flywheel energy storage
Flywheel energy storage
Flywheel energy storage works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy...
(FES) to store energy for traction, allowing electric systems to operate without overhead wires or third rails, and railcars fuelled by small gas, diesel or hydrogen engines, offering very high energy efficiency and very low emissions, suitable for new-build or existing rail systems in a variety of gauges, serving both urban and rural communities in any part of the world.
Current usage
London MidlandLondon Midland
London Midland is a train operating company in the United Kingdom. Legally named London and Birmingham Railway Ltd, it is a subsidiary of Govia, and has operated the West Midlands franchise since 11 November 2007....
, owner of the West Midlands franchise, began operating a single PPM50 (Class 999) unit on the Stourbridge line on Sundays in 2002, with a Class 153 Diesel multiple unit
Diesel multiple unit
A diesel multiple unit or DMU is a multiple unit train consisting of multiple carriages powered by one or more on-board diesel engines. They may also be referred to as a railcar or railmotor, depending on country.-Design:...
(DMU) providing a weekday service. In June 2009, the Class 153 was replaced by two PPM60 units, classified as Class 139
British Rail Class 139
British Rail Class 139 is the TOPS classification for PPM60 model lightweight railcars built by Parry People Movers, for use on the British rail network...
(with another as spare), providing a 10-minute frequency in both directions. Although the capacity of the unit (60 passengers) is less than the DMU, overall capacity is increased due to the greater frequency, up from 4 to 6 trains per hour.
From 24 January 2011, Go! Cooperative
Go! Cooperative
Go! Cooperative Ltd, now trading as GOCO, is an open access UK Train Operating Company which is currently proposing to operate a service between Yeovil and Birmingham, via Oxford...
planned to be operating a trial service between Alton
Alton railway station
Alton railway station is a railway station in the town of Alton, in the English county of Hampshire. The station is the terminus for two railway lines; the Alton Line which runs to Brookwood and onto London Waterloo and the Mid Hants Watercress Railway, which runs to Alresford. The latter once ran...
and Medstead & Four Marks
Medstead and Four Marks railway station
Medstead and Four Marks railway station is a railway station in the English county of Hampshire, serving the villages of Medstead and Four Marks.-History:Opened in August 1868 as Medstead, it changed to its present name on 1 October 1937....
on the Mid-Hants Railway using the Class 999 unit. Due to technical issues however, this has been delayed until November 2011.
Earlier trials
Stourbridge Town Branch Line
The Stourbridge Town Branch Line is a railway branch line, in Stourbridge, West Midlands, England. It is claimed to be the shortest branch line in Europe, and many miniature railways are certainly longer....
in the West Midlands
West Midlands (county)
The West Midlands is a metropolitan county in western central England with a 2009 estimated population of 2,638,700. It came into existence as a metropolitan county in 1974 after the passage of the Local Government Act 1972, formed from parts of Staffordshire, Worcestershire and Warwickshire. The...
in 2006. Since Central Trains
Central Trains
Central Trains was one of the original 25 train operating companies to emerge from the break-up of British Rail between 1994 and 1997. The company operated local, urban and secondary express services across central England and Mid Wales.-Overview:...
had no Sunday service on the branch, the initiative was brought to test a PPM50 model at that time, with a view to replacing the Class 153
British Rail Class 153
The British Rail Class 153 Super Sprinter is a single car diesel multiple unit converted from British Rail Class 155s.-Description:These units were originally built as two-car Class 155 units by British Leyland from 1987–88, but were converted by Hunslet-Barclay at Kilmarnock from 1991-92...
single-car Diesel Multiple Unit
Diesel multiple unit
A diesel multiple unit or DMU is a multiple unit train consisting of multiple carriages powered by one or more on-board diesel engines. They may also be referred to as a railcar or railmotor, depending on country.-Design:...
that previously worked the Branch with a unit with much lower operating costs. The trial lasted for a year.
Parry People Movers have also been demonstrated on narrow gauge railways (Welshpool and Llanfair Light Railway
Welshpool and Llanfair Light Railway
The Welshpool and Llanfair Light Railway is a narrow gauge heritage railway in Powys, Wales. The line is around long and runs westwards from the town of Welshpool via Castle Caereinion to the village of Llanfair Caereinion. The track gauge is ....
, Ffestiniog Railway
Ffestiniog Railway
The Ffestiniog Railway is a narrow gauge heritage railway, located in Gwynedd, Wales. It is a major tourist attraction located mainly within the Snowdonia National Park....
, Welsh Highland Railway
Welsh Highland Railway
The Welsh Highland Railway is a long restored narrow gauge heritage railway in North Wales, operating from Caernarfon to Porthmadog, and passing through a number of popular tourist destinations including Beddgelert and the Aberglaslyn Pass. At Porthmadog it connects with the Ffestiniog Railway...
).
Technology
PPMs utilise rotating flywheels as a store of kinetic energy which is then used to power the vehicle. A typical PPM flywheel is made from steel laminateLaminate
A laminate is a material that can be constructed by uniting two or more layers of material together. The process of creating a laminate is lamination, which in common parlance refers to the placing of something between layers of plastic and gluing them with heat and/or pressure, usually with an...
s, approximately 1 m in diameter and 500 kg in mass, designed to rotate at a maximum speed of 2,500 rpm. The flywheel is mounted horizontally at the centre of the unit, beneath the seating area.
The flywheel
Flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...
allows the direct capture of brake energy (when slowing down or descending gradients) and its re-use for acceleration. Since the short-term power demand for acceleration is provided by the energy stored in the flywheel, there is no need for a large engine. A variety of small engine types can be used including LPG, diesel
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
or electric traction.
On a route with stations a short distance apart it is theoretically possible to use the unit as a tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...
without any engine or overhead electrification at all. Instead the flywheel could be re-energised at each station storing enough power to carry it on to the next.
Fleet
| Class | Operator | No. Built | Year Built | Cars per Set | Unit nos. | Length | Seated | Standing |
|---|---|---|---|---|---|---|---|---|
| Class 139 British Rail Class 139 British Rail Class 139 is the TOPS classification for PPM60 model lightweight railcars built by Parry People Movers, for use on the British rail network... |
London Midland | 2 | 2008 | 1 | 139001 - 139002 | 9.6 m | 25 | 35 |
| Class 999 | Pre-Metro Operations | 1 | 2002 | 1 | 999 900 | 8.7 m | 20 | 30 |