Abstract: A method for operating vehicles, in particular track-bound vehicles, permits two vehicles to approach one another even to comparatively short distances and at the same time can be implemented with comparatively low expenditure. For this purpose, a collision by a first vehicle towards the rear of a second vehicle is detected by the second vehicle, a warning message is emitted by the second vehicle triggered by the detection of the collision or running into from the rear, and a braking process is triggered by the first vehicle on the basis of the warning message emitted by the second vehicle. A device for a vehicle which detects the collision of a further vehicle is also provided.

Abstract: A high temperature proton exchange medium (PEM) fuel stack system includes features for enhancing the thermal management of the fuel cell. The fuel cell can include a plurality of membrane-electrode-assemblies (MEA) separated by bipolar plates. The upper and lower edges of the bipolar plates are configured such that a plurality of fins is formed therein. Air can be passed along the fins in the upper edges of the plates and along the fins in the lower edges in opposite directions. A plurality of channels is formed on one or both surfaces of the bipolar plates. The channels extend along a serpentine path. Except for the end plates, hydrogen is supplied to the channels on one side of each plate and air is supplied to the channels on the channels on the opposite side of each plate. Such features keep the fuel cell within acceptable temperature limits during operation.