This series was designed in the 1980s thanks to trials of a new type of stock to cover requirements for the major rise in transport demand in large Spanish cities. Initially, the 445.001 prototype was developed and built by domestic manufacturers with support from the Centre for Technological and Industrial Development (CDTI). This initiative was modified to construct the 446 series, which has a different configuration (Engine-Trailer-Engine) to previous series: over 2,000 kW of power; an acceleration of over 1m/s2; an interior layout enabling 700 seated and standing passengers; greater accessibility, and new amenities for passengers. A modernisation and extended useful life process for the series began in 2005.
The interior layout of the carriages is the same, except for the driver's cab of each engine carriage, where the control desk, the top devices panel and the cabinets with the low voltage apparatus, the air conditioning control and communication, information and safety equipment are located. Only two control cabinets are located in the trailer carriage.
Access is made via three platforms equipped with automatic double nesting-sliding doors, with an opening of 1,300 metres, and moving platforms that provide four passenger compartments with fixed and folding seats and central corridor. On the trains of the 1st and 2nd series, the door was pneumatic, while in the 3rd series it is electric.
The interior lining of the walls and ceiling is polyester, with a rubber floor. Luggage racks, handle bars and bins complement the interior.
The lighting is fluorescent along a central channel, with halogen light points on the sides.
The TU has display monitors inside and outside the vehicles, which help passengers to know the destination of the train, the next stop, the possibilities of taking other means of transport at the next station, and the outside temperature. In addition to this written information, passengers can also receive information through the PA, either digitised in the case of the automatic announcement of the stations, or produced by the driver if he/she has to report any incidents. It also has an installation to play ambient music.
The temperature control system, both heat and cold, is integrated into the roof of the central platform. There are floor-level heaters to back up the heating system.
In the late 1980s, and faced with the strong social demand for quality transport in the vicinity of large Spanish cities and the absence of a material suitable for this type of services, Renfe decided to acquire a material designed specifically to satisfy this type of traffic. Its purchase is among the actions provided for in the so-called "Felipe Plan" to improve access to large cities.
These new trains had to be characterised by greater specific power to develop greater accelerations, due to the numerous stops and short distances between stations, and an internal distribution that allowed for a greater standing capacity.
With these demands, the 445.001 unit was built, which is a prototype with "chopper" equipment, designed to test various innovative solutions. The prototype was developed and built by five national manufacturers (MTM, GEE, Macosa, CAF and WESA) with financial support from the Centre for Technological and Industrial Development (CDTI). The negative test results of this prototype prompted Renfe to give up on this vehicle. However, the conclusions derived from the 445 unit made it possible to move forward with the design of future commuter units.
The 446 TU was Renfe's first series of material designed specifically for the commuter service, noteworthy due to its reliability, maintainability, high comfort and low energy consumption, as well as for its excellent acceleration and deceleration performance, which have made them ideal for the provision of these types of services.
446 units were purchased in several batches. The first batch of 50 TUs in 1987, followed by another 50 trains in 1988. These 100 trains, delivered between July 1989 and December 1991, entered commercial service, after the testing of the TU prototype, in November 1989 on the Cercanías lines from Madrid to Parla and Fuenlabrada.
Subsequently, and following excellent operating results, another 70 trains were purchased in May 1991 and received between May 1992 and May 1993. This batch has certain differences compared to the previous 100 trains, such as that the doors are electric, they have updated PA and ambient music, and cushions were installed in the seats.
In total, 170 trains were purchased from the 446 series, of which, and as a result of the bombing on 11 March 2004, three S-446 electric railcars were decommissioned. All 446 series trains were built by Caf, Cenemesa, Conelec, Macosa, M.T.M and Melco
Each unit consists of two engine carriages with identical cabs (M), between which is an intermediate trailer (IT). The train's axle arrangement is Bo'-Bo'-2'-2'- Bo' Bo'. They can circulate in multiple control up to 3 units.
Unlike the previous series (436, 439 and 440), the 446 has a different configuration (M-R-M), a power greater than 2,000 kW, acceleration of more than 1 m/s2, an interior distribution that allows transporting 700 people between seats and standing; greater accessibility, which translates into three doors per side in each carriage and new features for customers: Air conditioning, passenger information systems based on microprocessors, ambient music, etc.
The 446 units have chopper technology, already tested in the latest units of the 440 series (501 and 502) and DC engines. Although the advantages of three-phase traction were already valued, it was not possible to use this technology in the 446 TU because there was no validated project for this type of 3000 V equipment, but it was incorporated in the 447 series.
In January 2005, a process began to modernise and extend the half-life of all the units that make up the series, lasting for five years, and carried out at the Central Repair Workshop in Valladolid. Improvements are related to equipment that has been subjected to increased wear, including mechanical, electrical and electronic and auxiliary elements, as well as control and image elements. In addition to the installation of new elements and components in the primary and secondary suspension, traction chopper, contact breaker box, air conditioning equipment, static converters, special attention will be paid to improving the interior lighting of the train by installing new fluorescent lamps in the central light fixture and four additional halogen lamps on the ceiling of each platform. In addition, the interior panels will be treated with antigrafitti paint, and a new upholstery will be placed on the seats, as well as new floors.
Body
The body's structure is self-supporting, formed by laminated profiles and steel and copper sheets electrically welded to the arc. On this structure are welded the subsets of sheet metal that form the side walls (made of tensed sheet metal to avoid irregularities), the end carriages and the ceiling. Although we tried to make the body's from aluminium from the outset, it was not possible because the right technology was not available.
The end carriages are made of high strength polyester, attached to the structure with tubular rivets, glue and sealer, designed to absorb energy in case of frontal impact. A large anti-impact armoured window provides the driver with visibility and protection.
The sides of the train, which are slightly sloped, are fitted with reflective glass windows arranged in the form of a continuous band. Each window has a second glass on the inside, and they are all armoured. It also has longitudinal fibreglass skirts that hide the equipment inside. There are moving footboards under the doors that move outwards as the doors open. All carriages are interconnected by manually operated doors and rubber tunnels. The interior layout of the carriage is the same, except for the space dedicated to the driver's cab of each engine carriage.
Each carriage has three platforms for passenger access - with two double nesting-sliding doors with an opening of 1,300 mm, each with retractable sliding footboards - that make up four passenger compartments with fixed, folding seats and central corridor. The floor height is relatively low (1,150 mm) and uniform throughout the train.
Under the chassis of the engine carriages are, among others, the chopper box, chokes, static converter, and the inverter box, while trailer carriage houses the circuit breakers, disconnectors, the compressor, the dryer, pneumatic panels and a temperature control condensing unit. The braking resistors are on the roof of each engine carriage and the two pantographs and lightning rods on the trailer.
Bogies
There are two double-axle bogies per carriage, with superficially tempered solid wheels, grease boxes with bearings and elastic crank guidance. The primary suspension uses coil springs, with the secondary suspension being pneumatic. Both have vertical shock absorbers, with the secondary suspension also having horizontal shock absorbers.
The bogie's chassis is made of welded steel. The body rests on the chassis, with no bogie bolster, so horizontal loads are transmitted by pivot and drag rods. The engine bogie has two suspended traction motors, which drive the axles by means of an elastic coupling and gearbox.
The engine bogie brake consists of wheels and blocks (they were removed in the 3rd series) and trailer carriage uses brake disks. The cylinders have a built-in accumulator spring for the parking brake.
All axles have tachogenerators The end axles have flange grease and railguards-snowplows.
Power and control electrical equipment
The power and control equipment consists of two traction and electric brake circuits, identical but independently operating, each one installed in each engine carriage, except for the common parts that are located in the trailer carriage.
The power collection equipment, common to both sets of power equipment, consists of:
The traction equipment, located in each of the two engine carriages, is equipped with chopper technology. Each set of power and control equipment of each engine carriage is basically composed of:
These units cab drive at a preset speed.
Brake systems
The TU has the following brake systems:
The service brake is combined, electric and/or pneumatic and recovers energy to the extent that the catenary admits it.
Auxiliary and pneumatic equipment
The auxiliary electrical equipment for lighting supply, traction control, temperature control and battery features two static converters with 3,000 Vcc, 85 KVA, 380 KVA output and 72 Vcc. In the event of a converter failure, the unit is automatically fed with 50% of the temperature control and lighting.
Temperature control features are 34,500 kcal/h in each carriage (22 kW) and 34.5 kW per carriage in heating. Air is produced by a main compressor powered by a 12 kW motor with a capacity of 1,400 litres/min. 10 bar. The air is stored in 200 litre tanks and is used for the service, emergency and dead man pneumatic brake, pneumatic suspension, door opening and auxiliary services. It also has a 1 kW auxiliary compressor to raise the pantograph and operate the main circuit breaker.
Other equipment
This unit's equipment includes a Scharfenberg mechanical, pneumatic and electrical coupling, being automatic in free end carriages and semi-permanent in coupled end carriages.
It is also equipped with an analogue ground train communication system, radio-telephone with the Traffic Control Centre and the Commuter Control Post, with GSM technology.
Driving aid is equipped with a self-diagnosis system and computer equipment to detect faults and assist with their resolution by means of a display in the cab, Asfa equipment, train-ground radio link system, double-acting dead man, and flange greasers.
Lastly, 74 units operating on the Madrid C5 line have been equipped with automatic driving systems (LZB).