Revision of limit value for longitudinal forces in the train
evaluated
Safety requires a limitation of the permissible longitudinal force exerted on the locomotive by the following cars. For some loco-hauled trains, this is a critical restriction for the use of regenerative braking. A more differentiated concept for the limit values for longitudinal forces could remove this barrier.
Technology field:Regenerative braking and energy management
General information
General criteria
Status of development: in use
Used in Switzerland.
Time horizon for broad application: in < 2 years
(no details available)
Expected technological development: not applicable
Concept is not technological.
Motivation:
Energy saving through increased recuperation
Benefits (other than environmental): small
Less wear of brakes through increased use of regenerative braking.
Barriers: medium
Safety
The limitation of longitudinal forces is relevant for derailment prevention and therefore very safety critical. A modification of the regulations would require extensive safety audits.
Success factors:
(no details available)
Applicability for railway segments: high
Type of traction: electric - DC, electric - AC
Type of transportation: passenger - main lines, passenger - high speed, passenger - regional lines, passenger - suburban lines, freight
Modified limit values for permissible longitudinal forces in the train would obviously affect all trains but the changes would be relevant only for loco-hauled stock since MUs have driven axles along the entire train. From the point of view of energy efficiency, the measure is only interesting for electric stock.
Grade of diffusion into railway markets:
Diffusion into relevant segment of fleet: not applicable
Share of newly purchased stock: not applicable
(no details available)
Market potential (railways): not applicable
(no details available)
Example:
SBB
Swiss SBB have introduced a differentiated concept for the limitation of longitudinal forces. Whereas most railways use 150 kN for all trains, SBB have increased the permissible forces to 240 kN for most trains with some restrictions (to 150 kN) for some freight trains.
Environmental criteria
Impacts on energy efficiency:
Energy efficiency potential for single vehicle: (no data)
Energy efficiency potential throughout fleet: (no data)
It is difficult to assess the energy efficiency effect of modified regulations for longitudinal train forces. Influencing factors are:
The share of trains affected by such the modification
Other limitations to an increased use of regenerative brakes (braking power, adhesion etc.)
Other environmental impacts: neutral
Economic criteria
Application outside railway sector (this technology is railway specific)