Monday, 17 December 2007

Class 395 Trainsets

The first Class 395, shown in Hitachi's Ashford maintenance depot, is currently involved in pilot trials.

Hitachi have a long history of supplying railway equipment in Japan. Before entering the U.K. market, they converted redundant British Rail 25kV EMU vehicles to prove the suitability of the Hitachi traction package on the so-called 'V-train' (V for Verification). They are now supplying Class 395 'Javelin' trains intended to provide a fast service to the 2012 Olympiad and improve commuting in parts of the South East.

Class 395 trainsets (‘units’) are a high-speed variant of the family of 'A Trains' built by Hitachi in Japan. They are 6-coach (‘car’) Electric Multiple Units (EMU) numbered from 395001, the first unit, upwards. Each vehicle is carried on two four-wheel bogies provided with air suspension. There are two types of vehicle – ‘DPT’ (Driving Pantograph Trailer) and ‘MS’ (Motor Standard Class). The vehicles are individually numbered – in the first unit the numbers are 39011 (DPT1), 39012 (MS1), 39013 (MS2), 39014 (MS3), 39015 (MS4) and 39016 (DPT2). The vehicles for the second unit (395002) number from 39021. Thus, the vehicle number identifies both the set and the position in the set. The trainsets are designed to be used on 750 volts d.c. and, in the future, 25kV a.c. on Network Rail infrastructure. The trainsets will also be used on CTRL infrastructure at 25kV a.c.

The two DPT end vehicles have driving cabs with a full control, monitoring and signalling installation (including TVM/KVB cab control and TPWS). There is a retractable nose fairing, revealing a Scharfenberg auto-coupler from Voith-Turbo in Germany. Each DPT also has a Faiveley pantograph, 25kV a.c. distribution and an underbody mounted main transformer. A high tension (25kV a.c.) bus is carried on the roof along the length of the train to interconnect the two DPT cars. This bus is a standard feature on Japanese 'Shinkansen' trains. The standard method of operation is for the rear pantograph to be raised and in use, thus the main transformer in the leading DPT is powered via the high tension bus. An emergency mode allows the leading pantograph to be raised. Associated with each pantograph is a roof-mounted Vacuum Circuit Breaker (VCB) and High Voltage Potential Transformer (HPT). The VCB is controlled from an equipment panel adjacent to the TPWS Control Unit. The a.c. return is taken via earthing devices fitted to each axle of the DPT, comprising carbon brushes contacting a collector plate fitted to the end of the axle.

Two secondary windings on the main transformer in DPT1 feed (via twisted-pair cables) solid-state Auxiliary Power Supply (APS) units underbody mounted, one on MS1, one on MS2. Four further secondary windings on the main transformer in DPT1 feed (via twisted-pair cables) solid-state underbody mounted traction converters, one on MS1, one on MS2. Similarly, the main transformer in DPT2 feeds the APS units and traction converters in MS3 and MS4.

The DPT vehicles are also provided with Brecknell & Willis 750 volt d.c. shoegear which may be raised and lowered as required. The shoegear feeds the DC bus which runs the length of the unit and feeds the traction converters on each of the motor cars (MS1-MS4). All cables are taken between cars via bolt connections and jumper cables. The four intermediate vehicles have 750 volt d.c. shoegear, switchgear and earthing contactors. There is a shore power connector (allowing the set to be powered from the trolley system in the depot where third rail is not provided). The d.c. return is taken via radial earthing devices fitted to each axle on motor cars, comprising carbon brushes contacting the axle in between the wheels. Each axle is driven, via a gearbox, from a three-phase motor mounted adjacent to the axle.

Related posts on this website

Testing Class 395 Trainsets.

[Related post ref added:10-Sep-2016]