In the project a software was developed and installed which allows one train to supply two trains with the electricity necessary for overnight heating. Before the measure, every train took the electricity from the catenary and transformed it to the necessary voltage for heating (thus producing high transformer losses). Thanks to the software it is possible to couple two train sets together in such a way that one is supplied by the other (thus saving the transformer losses of one of the trains). The stand-still energy consumption of the trains can thus be reduced by 25%. The operation scheme itself was not modified: The temperature inside the coaches is 22 degrees C during service and is reduced to 15 degrees C during overnight stand-still periods.
The software has been installed in all of the 44 train sets of type ER 4. A change in the software of ER 4 trains, that had to be done anyway, was used to integrate the software. The measure is finished. The measure saves energy only if two train sets happen to stand together in the stand-still areas. Since the system of overnight stand-still has not been changed for the measure, this is not always the case, but only for about 50% of the train sets resting in stations over night.
The costs for the project were rather low. Even though it proved difficult to convince the technical department. This has taken years, and was only successful when the ground level (technicians in the workshop) was addressed and measurements on the ground level showed the potential lying in this measure.
Another method of reducing stand-still energy consumption had been discussed prior to the project: installing a timer to reduce the coach temperature to 5 degrees C during the night and then automatically raise it to 22 degrees C before service. This has not been done for two reasons: It can not be ruled out that in exceptionally cold periods the inside temperature would fall below 5 degrees C with consequences such as water freezing in the toilets etc. Furthermore the coaches have to be warm when the trains are cleaned. However the time the cleaning personnel arrives varies too much to program the timer in a way to take care of that.