Our experience – your benefit: replaceable front end

Vectron – a product of our experience, for your future: The further development of passive safety is another area where Siemens is playing a pioneering role. And in doing so, we’re not just focusing on standards-based requirements but on customer benefits. That’s because in addition to mere compliance with standards, we always strive to generate the best possible advantages for our customers. Naturally, this also applies to passive safety.

Benefits at a glance

  • Secure escape routes

  • No deformation of locomotive body

  • Repair possible without welding or straightening work

  • Reduced downtimes

  • Reduced insurance premiums due to reduced repair costs and downtimes

  • Front end can be purchased or stocked as replacement part


High-capacity deformation elements

Beginning around 1970, wear buffer beams were used to minimize collision damage to locomotives. Due to their construction, such buffer beams had the disadvantage that the forces passing through the buffer did not feed directly into the car body structure. The fault was in the attachment of the buffer beam to the locomotive body, which was not in alignment with the buffer, thus causing bending stress in the buffer beam. To eliminate this problem, Siemens developed a combination of innovative buffers with spring rings and hydraulic capsules, as well as patented high-capacity deformation elements, which were first used in 1997 on the Deutsche Bundesbahn's Class BR152 locomotives.

Functioning of the deformation elements

The functioning is as follows: As of a defined buffer force, the deformation element effectively crumples before the locomotive is damaged. In a first stage, the energy is absorbed through the buffer, and in a second stage, through the crumpling of the deformation element. Since 1997, this concept has been implemented on Siemens Class ES64U2, U4 (“Taurus”), ES64F4 (BR189) and ER20 locomotives and continually improved by raising the level of energy absorption. The deformation element itself is a remarkably simple welded construction. The buffers are available from two suppliers; a proprietary solution was not implemented. Thanks to this new concept, there has been an unmistakable, proven reduction in collision damage to vehicles. Experience has also shown that this optimal combination of high-capacity deformation elements and driver’s cab design results in excellent protection of personnel.

Example: Accident involving a Class Rh1116 locomotive

Collision at approx. 25 km/h

Collision at approx. 25 km/h: It is evident that apart from the deformation elements and buffers, the locomotive is practically undamaged – which is just as it should be.

Example: Accident involving a Class Rh2016 locomotive

Collision at approx. 30 km/h

Collision at 30 km/h: No deformation of the locomotive body – deformation element and buffer absorb all the energy.

Representative crash scenarios to EN15227

The examples show that definite progress has been made thanks to the safety concepts used. Nevertheless, serious accidents still result in extended repair and downtimes. A few years ago, efforts were made by standards organizations to develop representative crash scenarios and standardize behavior. Based on an analysis of 304 accidents, the European Rail Research Institute (ERRI) created a platform for defining representative scenarios that has since been set down in the EN15227 standard. The scenarios cover four out of five accidents observed. Naturally, there is no way to protect against all possible accident types. The standard defines general conditions for decelerations, survival space, escape route requirements, and overriding in the event of a collision. It also defines the exact obstacles to be considered.

Siemens safety concept

The guidelines for development engineers naturally include compliance with the specifications in the EN15227 standard. However, it is also necessary to eliminate the deficits resulting from long, accident-related downtimes devoted to repairing the car body structure. This yielded the additional requirement of finding a solution that would permit simple repairs and at the same time ensure the integrity of the locomotive body. Development efforts have resulted in a combination of the already proven concept of reversible buffers plus deformation elements and a replaceable front end. The survival space, comprising the driver’s cab and all doors, protects the locomotive driver and allows access and escape in emergencies. The locomotive body remains undeformed in all the scenarios defined by the TSI.

Test for validating the calculation model

TSI Scenario 3

Simulation of a frontal collision with a truck at 110 km/h as per TSI Scenario 3: It’s obvious that all the deformations in the front involve structures that are easily replaced. The survival space is secured. In addition to meeting specifications for survival space and deceleration values, the locomotive body remains undamaged.

Use of a replaceable front end

The replaceable front end has already been in use for some time. The first application was on the ER20CF for Lithuania. Due to the central buffer coupling as per GOST, only the replaceable front end may be used here.

The LE4700 for the Portuguese national railways (CP) has the complete safety package comprising high-capacity deformation elements and a replaceable front end.

The 120 Class HLE18 locomotives for the Belgian national railways are also equipped with the complete safety package comprising high-capacity deformation elements and a replaceable front end.

Vectron’s passive safety

Vectron will have the complete safety package comprising high-capacity deformation elements and a replaceable front end. The front end, including built-in components such as the driver’s console, will be identical for all classes.