Silverliner

Silverliner
A train with Silverliners II through V at Fern Rock
In service	SL-I: 1958-1990 SL-II: 1963-2012 SL-III: 1967-2012 SL-IV: 1973-present SL-V: 2009-present
Manufacturer	SL-I/II: Budd Company SL-III: St. Louis Car Company SL-IV: Avco,General Electric SL-V: Hyundai Rotem
Number built	SL-I: 6 SL-II: 59 SL-III: 20 SL-IV: 232 SL-V: 120
Formation	SL-I/II/III: Single unit SL-IV/V: Married Pair and Single Unit
Operator(s)	Pennsylvania Railroad Reading Railroad Penn Central Railroad Conrail (under SEPTA) SEPTA US DOT Denver RTD
Line(s) served	SEPTA Regional Rail
Specifications
Car body construction	Stainless steel
Doors	SL-I/II/III/IV 2 end doors w/ traps SL-V: 3 Quarter point (2+1), two w/ traps
Maximum speed	100 mph (160 km/h)
Traction system	SL-II/III/IV: Transformed alternating current fed initially through Ignitron and later Silicon-controlled rectifiers to phase angle DC motor controller. SL-V: IGBT fed AC Drive.
Electric system(s)	catenary 11-13.5 kV 25 Hz AC 12 kV 60 Hz AC (SL-V only) 25 kV 60 Hz AC (SL-V only)
Current collection method	Pantograph
Bogies	SL-I/II: Budd Pioneer SL-II/IV/V: General Steel GSI 70
Braking system(s)	Pneumatic, Dynamic (SL-IV/V only)
Coupling system	WABCO Model N-2

Silverliner is the name given to a series of electric multiple unit railcars in commuter rail service in the Philadelphia area since 1958. As of the introduction of the Silverliner V in 2009-2010, there have been 5 generations of Silverliner cars, identified by the Roman numerals I through V placed after the name Silverliner. The Silverliner name came from the classes' shiny stainless steel body shell compared with the painted (or rusting) carbon steel railcars placed in service by the Pennsylvania and Reading Railroads between 1915 and 1936. Applied to the first large production order in 1963, the cars made such an impression that the name has since been applied to all subsequent MU classes purchased by SEPTA for the Regional Rail services.

What came to be known as the Silverliner Is were a set of 6 pilot EMUs making use of Budd's prototype Pioneer III railcar design. The 6 Pioneer III cars were purchased in response to the increasing age of the PRR's MP54 fleet, some of which had been in service since 1915. While 100 of the MP54s had been rebuilt in 1950 with increased power and air conditioning, the old cars still suffered from a small passenger capacity, high weight and poor acceleration among other things. As other railroads adopted new technology MUs like the New York Central ACMU and New Haven 4400 series "Washboards" the PRR felt increasing pressure to update its fleet. In 1958 the PRR placed an order with the Philadelphia-based Budd Company for 6 Pioneer III MU cars in two subclasses to test out various options. Numbered 150 to 155 the even-numbered cars had fabricated truck frames and disc brakes, while the odd-numbered cars had cast steel truck frames and tread brakes. The PRR initially had hopes to MU cars such as the Pioneer IIIs in intercity service along its electrified routes and the cars were split between long distance and suburban duties. However as testing went on they were soon limited to suburban service in the Philadelphia area when a full-scale production order of 38 PRR "Silverliner" cars were delivered in 1963.