A railway electrification system supplies electric power to railway trains and trams without an on-board prime mover or local fuel supply. Electric railways use electric multiple units. Electricity is generated in large and efficient generating stations, transmitted to the railway network and distributed to the trains; some electric railways have their own dedicated generating stations and transmission lines, but most purchase power from an electric utility. The railway provides its own distribution lines and transformers. Power is supplied to moving trains with a continuous conductor running along the track that takes one of two forms: an overhead line, suspended from poles or towers along the track or from structure or tunnel ceilings, or a third rail mounted at track level and contacted by a sliding "pickup shoe". Both overhead wire and third-rail systems use the running rails as the return conductor, but some systems use a separate fourth rail for this purpose. In comparison to the principal alternative, the diesel engine, electric railways offer better energy efficiency, lower emissions, lower operating costs.
Electric locomotives are usually quieter, more powerful, more responsive and reliable than diesels. They have an important advantage in tunnels and urban areas; some electric traction systems provide regenerative braking that turns the train's kinetic energy back into electricity and returns it to the supply system to be used by other trains or the general utility grid. While diesel locomotives burn petroleum, electricity can be generated from diverse sources, including renewable energy. Disadvantages of electric traction include: high capital costs that may be uneconomic on trafficked routes, a relative lack of flexibility, a vulnerability to power interruptions. Electro-diesel locomotives and Electro-diesel multiple units mitigate these problems somewhat as they are capable of running on diesel power during an outage or on non-electrified routes. Different regions may use different supply voltages and frequencies, complicating through service and requiring greater complexity of locomotive power.
The limited clearances available under overhead lines may preclude efficient double-stack container service. Railway electrification has increased in the past decades, as of 2012, electrified tracks account for nearly one third of total tracks globally. Electrification systems are classified by three main parameters: Voltage Current Direct current Alternating current Frequency Contact system Third rail Fourth rail Overhead lines Overhead lines plus linear motorSelection of an electrification system is based on economics of energy supply and capital cost compared to the revenue obtained for freight and passenger traffic. Different systems are used for intercity areas. Six of the most used voltages have been selected for European and international standardisation; some of these are independent of the contact system used, so that, for example, 750 V DC may be used with either third rail or overhead lines. There are many other voltage systems used for railway electrification systems around the world, the list of railway electrification systems covers both standard voltage and non-standard voltage systems.
The permissible range of voltages allowed for the standardised voltages is as stated in standards BS EN 50163 and IEC 60850. These take into account the number of trains drawing their distance from the substation. Increasing availability of high-voltage semiconductors may allow the use of higher and more efficient DC voltages that heretofore have only been practical with AC. 1,500 V DC is used in Japan, Hong Kong, Republic of Ireland, France, New Zealand, the United States. In Slovakia, there are two narrow-gauge lines in the High Tatras. In the Netherlands it is used on the main system, alongside 25 kV on the HSL-Zuid and Betuwelijn, 3000 V south of Maastricht. In Portugal, it is used in Denmark on the suburban S-train system. In the United Kingdom, 1,500 V DC was used in 1954 for the Woodhead trans-Pennine route; the system was used for suburban electrification in East London and Manchester, now converted to 25 kV AC. It is now only used for the Wear Metro. In India, 1,500 V DC was the first electrification system launched in 1925 in Mumbai area.
Between 2012 and 2016, the electrification was converted to 25 kV 50 Hz AC, the countrywide system. 3 kV DC is used in Belgium, Spain, Slovakia, South Africa, the northern portion of the Czech Republic, the former republics of the Soviet Union, the Netherlands. It was used by the Milwaukee Road from Harlowton, Montana, to Seattle, across the Continental Divide and including extensive branch and loop lines in Montana, by the Delaware, Lackawanna & Western Railroad in the United States, the Kolkata suburban railway in India, before it was converted to 25 kV 50 Hz A
The Percuil River is an estuary and stream draining the southern part of the Roseland Peninsula of Cornwall, UK and is one of three major tidal creeks of the River Fal. The small port and holiday destination of St Mawes is on the western shore and is linked to Place Creek on the eastern shore by the Place Ferry; the ferry is used by walkers on the South West Coast Path. The Percuil River is one of three major tidal creeks of the River Fal which flows into the deep tidal basin of Carrick Roads and out into Falmouth Bay; the creek is a ria, or drowned river valley which started to form in the Quaternary period. Sea-level rise during the Ipswichian interglacial flooded the valley, followed by the Devensian glacial, where sea-levels fell to 42 m below today's tides and the River Fal cut a deep sinuous valley into the bedrock; as the climate warmed, sea-levels rose again and the arctic tundra gave way to woodland. The sea continued to rise drowning the trees, leaving peat deposits which have been exposed nearby at Maenporth and Famouth.
The stream and estuary combined is 11 kilometres long and rises to the north of the A3078 near Treworthal. The highest tidal limit is at Trethern Mill where the streams runs for 6 kilometres to enter the River Fal between Castle Point and Carricknath Point. At Trethern Mill the river is known as Trethem Creek and there are four named minor creeks on the eastern side of the Percuil River where the valley of small streams enter the estuary. From north to south they are Pelyn Creek, Porth Creek and Place. Within the estuary the steep-sided banks provides a sheltered harbour in contrast to the exposed coast of Falmouth Bay, the eastern coast of Roseland; the land around is anciently enclosed farmland containing well-drained, fine loamy soils with both arable and pastoral farming. Of similar early origin are the network of roads and farmsteads which surround the stream, with the exception of the lower eastern bank from St Mawes Castle to beyond Povarth Point, late 20th-century housing. First mentioned in 1284 as Lavada or Lavousa and containing the element lann indicating an Early Christian enclosure, St Mawes never became a parish despite, in 1381 having a licensed chapel and holy well.
The village became a borough in the early 14th-century and the quay was first mentioned in 1539. From medieval times St Mawes was a busy fishing village and port despite being vulnerable to attack from Breton raiders. With the building of St Mawes Castle, one of Henry VIII's device forts, constructed to the south-west of the village between 1540 and 1542, the open sea became safer. Crab and the pilchard fisheries developed and pilots could reach incoming ships before their Falmouth rivals; as the port expanded supporting industries such as ropewalks, pilchard cellars and inns developed, a watch-house was provided for the coastguard service. Maritime industries declined with the opening of the railway to Falmouth in 1863, to be replaced with a passenger steamer service, holiday destination and an exclusive residential and retirement village in the 20th-century. Opposite St Mawes is the small tidal creek of Place, the destination of the Place Ferry from St Mawes, the departing or landing point for walkers on the South West Coast Path.
The boathouse and slipway was used by the Percuil and St Mawes Ferry, for the twice daily steamer from Falmouth and the rowing ferry to St Mawes. Passenger traffic was for estate workers and to take children to school. With the increasing use of roads the ferry became redundant but the service restarted in the 1980s, with the support of the Countryside Agency following the designation of the coast path as a National Trail; the sheltered beach on the southern shore, known as Cellar Beach was once the landing place for large catches of pilchards. Cellar refers to the spot where the pilchards were salted as a winter food for local consumption and for export to Mediterranean countries. Much of the wealth of the Spry family came from their fishing fleet, pilchard cellar and boat-building; the parish of St Anthony in Roseland is mentioned in the Domesday Book when it belonged to the Bishop of Exeter. Place House is on the site of a small monastic cell which housed an Augustinian priory and one monk dating to sometime after 1140 when the parish was given to the Priory of Plympton in 1288.
Place Priory was destroyed by French pirates in 1338 and dissolved in 1538. A map of 1597 shows what appears to be an Elizabethan mansion built on the site and belonging to a Mr Davies; the house has been altered and enlarged over the years, in 1851 remodelled by Sir Samuel Spry, the MP for Bodmin to give Place House its present-day appearance of a French chateau. In front of the house was the pond of a tidal mill, known to have been in existence in 1540, would have been used to mill grain for the priory, it was still working in 1812 and the lease was advertised in 1848. The pond was reclaimed from the sea in circa 1860 when the house was rebuilt, is now the lawn in front of the house; the house was requisitioned by the War Office during World War II. St Anthony's church has been described, by Nikolaus Pevsner, as the best example of what a Cornish parish church looked like during the 12th and 13th-centuries; the church is unique because it retains it original medieval cruciform plan despite a 19th-century restoration by the Reverend Clement Carlyon, employed by his cousin Sir Thomas Spry.
John Abdo is an American health and fitness expert & coach, nutritionist, motivational speaker and a TV personality. He has worked as a Strength & Conditioning Coach for numerous U. S. Olympic team athletes for the 1976, 1980, 1984, 1988 Olympic Games. Abdo has been a part of fitness profession for more than four decades and was inducted into the National Fitness Hall of Fame in 2007, he has authored several books including Body Engineering, "Make Your Body a Fat-Burning Machine", "Ultimate Sexual Health & Performance", "Brain Sensation & Motivation". His AB-Doer invention was popular, has generated five-hundred million dollars in sales since 1997. John is the formulator and spokesperson for Androzene, a male sexual-health supplement, Flozene, a prostate health formula for men. Official website John Abdo on LinkedIn