Electric engine S-253

Renfe is renewing its engine fleet for freight with the 253, increasing reliability, availability, and load and traction capability. The engine is Iberian gauge, although it is prepared for installing UIC gauge bogies, and single voltage to travel under 3-kilovolt catenaries. It offers 5,400 kilovolts of power with IGBT invertors and Mitrac traction controls, and a transmission module to reach a maximum speed of 140 km/h.




In 2006, we awarded Bombardier the purchase of 100 electric locomotives as part of the strategic plan for the renovation of the Freight fleet.. This is the first time that Renfe has acquired this type of engine material, intended exclusively for freight traffic.

With this purchase, Renfe renewed its fleet of Freight and Logistics locomotives, taking into account the necessary effectiveness and profitability of this area in a sector of activity open to competition. The new locomotives provide increased reliability, availability, and load and traction capacity, as well as increased cost and energy efficiency and, in short, increased production efficiency.

These electric locomotives, which make up the 3rd generation of Bombardier's Traxx family of machines with which it has 95% of its components is common with the Traxx family, are designed to run at a maximum speed of 140 kilometres per hour, with an increase in power of about 67%. This makes it possible to carry 30% more load on the same track gradient and speed conditions. They also increase availability by 15% to 95%, and reduce maintenance costs by 50%.

With this purchase, thanks to the increased cargo capacity and increased availability of the 253, the production capacity was increased for the transport of goods. In terms of availability and maintenance, it was envisaged that the 253 locomotives would have an incident every 250,000 kilometres, compared to 33,000 kilometres per incident so far, with an availability of 95% compared to the previous material, which reached 25%.

Given these characteristics, it was possible to increase heavy freight and large tonnage traffic whilst passing through areas with steep gradients. Another advantage of the 253 as a result of these characteristics is their lower environmental impact.
Another noteworthy point of this acquisition is that the manufacture and maintenance of these locomotives was carried out jointly between Bombardier and Renfe. The workshops of the Maintenance and Manufacturing Area that participated in the manufacturing and assembly work of this locomotive are located in Villaverde and Vicalvaro (Madrid), and Can Tunis (Barcelona).

55 locomotives were almost entirely assembled at the Bombardier factory in Vado Ligure, Italy, and subsequently sent to Integria's workshops for completion, coupling between the body and the bogie, and testing. With regards to the remaining locomotives, the first phase of assembly was carried out in Vado Ligure, and Integria carried out the rest of the assembly work, the coupling between the body and the bogies, and the operating tests.

The electrical cabinets of 11 locomotives were manufactured at the Bombardier factory in Kassel (Germany) and the remaining 89 were made in Renfe's workshops.


This series of locomotives is single voltage for driving under 3-kilovolt DC catenaries. They have 5,400 kilovolts of power with IGBT invertors, Mitrac IGBT traction controls, and a transmission module to reach a maximum speed of 140 km/h. The locomotives are Iberian gauge, although UIC gauge bogies can be installed.


This series of locomotives is intended exclusively for freight traffic. The power is 5,400 kW to reach a maximum speed of 140 km/h. The traction system is controlled by IGBT microprocessor technology and is powered exclusively by 3-kilowatt single voltage, running on Iberian gauge tracks.


The body has a modular structure with dimensions of 18,900 mm in length between stops and 2,977 mm. maximum width. The locomotive has two large cabs at each end that can be accessed from either side (four doors in total) and is equipped with a desk with an ergonomic design that allows the driver access to all controls and systems from a sitting position. The engine room takes up all the space between the two pressurised and ergonomically designed cabins. The cabs are made of anti-penetration steel and include an impact absorption zone, with replaceable stops and elements, and anti-slip devices.

The cabin temperature control system includes air conditioning, heating and ventilation equipment. The air conditioning consists of two modules, one central and one additional located on the roof of the cabin, which ensures comfort during Spain's high temperatures.

Traction systems

The 253 has 4 asynchronous three-phase engines, which are suspended by the nose and provide a power of 5,400 kilowatts, representing 7,337 horsepower. The rated power is 5,200 kilowatts under normal voltage conditions between 3060 and 3600 watts. This power provides maximum traction force at start-up of 300 kilonewtons.

Traction and auxiliary equipment are managed by the Mitrac system, which includes the following subsystems:

  • Water-cooled IGBT traction converters to transform from catenary voltage and power the motors.
  • Auxiliary converters, which supply power to auxiliary systems, including lighting and air conditioning.
  • Electronic subsystems to manage train communications and control the propulsion system.

Bogies and brakes

Each locomotive has 2 'Flexifloat' bogies for Iberian gauge tracks with Bo'Bo configuration and a mass of 16 tons together with the engines. The load is transferred between the bogies and the body by means of two drawbars.

The 253 locomotive has several types of brakes, which are manufactured by Knorr under UIC standards. The electrodynamic brake is regenerative and rheostatic, and has a braking force limited to 200 kilonewtons, with a maximum brake power of 2,600 kilowatts. Being regenerative, the energy produced in braking is reused, allowing a 10% savings in energy consumption, in addition to demanding less traction force at start-up.

It also has two types of pneumatic disc brake that are electrically controlled, an indirect auto actuator and a non auto actuator. The parking brake is 46-tonne spring accumulator.

Control and auxiliary system

These locomotives have the Asfa Digital security system, with the exception of the first 5 that have conventional Asfa, so they will have a different configuration on their desks. All locomotives are pre-installed with Ertms. The driving options include automatic speed control by pre-set speed (TFA), which the original Traxx rail carriages did not have

The representation of the processes of the 253 machine can be seen on the desk of the cabs on both the diagnostic and the Asfa and Ertms screens. The diagnostic touch screen is intended to provide the driver or maintenance personnel with information on the operational status of the locomotive or those that form part of the double traction. It also indicates equipment failures and workshop diagnostics. This Teloc system is integrated in this diagnostic screen for recording the operational data of the locomotive (speed, signals, traction/brake stress, alarm pushbutton, among others).

There are various devices distributed around the carriages to stop the locomotive or the train. The cabs do not have mirrors since they have innovative digital rear view video cameras, which show the images on the diagnostic screen.

The 253 stops feature collision shock absorbers that absorb a large part of the energy in the event of a head-on collision.
This locomotive has two auxiliary service converters with a power of 180 kilowatts each, amounting to a power supply of 3 X 460 watts at 60 hertz, and 110 watt DC batteries.

Technical Features

  • Number of units: 100.
  • Gauge: 1.668 mm.
  • Supply voltage: 3,000 V DC.
  • Driver's cabs: 2.
  • Number of engines: 4 three-phase asynchronous engines.
  • Total power: 5,400 Kw / 7,337 hp.
  • Traction force at start-up: 300 kN.
  • Main compressor: 2,400 l/m with oil piston.
  • Auxiliary group: 2 converters.
  • Mass: 87 t.
  • Mass per axle: 21,8 t.
  • Maximum speed: 140 Km/h.
  • Arrangement of bogies: Bo’Bo’.
  • Bogie mass: 16 Tn with engines.
  • Wheel size: 1,250/1,170 mm.
  • Pneumatic brake: Disc.
  • Electric brake: Regenerative and rheostatic.
  • Parking brake: Accumulator spring.
  • Multiple command: YES.
  • Pantograph: Stemmann Technik.
  • Cabin signage: Asfa Digital and Ertms.
  • Builder: Bombardier.
  • Services: Freight.

Dimensions and weights

  • Weight 87 Tn.
  • Length between stops: 18.900 m.
  • Body width: 2.997 m.
  • Maximum height: 4.270 m.
  • Bogie tie: 2,600.
  • Wheelbase: 10.390 m.