In much of Europe it gets awfully cold in winter time, which presents difficulties for rail operators when carriages are parked overnight in a siding, and need to be warmed up the next morning ready for passengers to board. Their solution – converting retired locomotives as a power supply for the carriage heaters.
“Heizlokomotives” in the age of steam
During the days of steam, the heaters inside each carriage were fed with steam from the boiler of the locomotive that was hauling the train. This presented difficulties each morning as the train would needed to be preheated before departure, so rather than monopolising a mainline steam locomotive, retired locomotives were retained as source of steam.
German-language Wikipedia explains the modifications made to retired locomotives for their role as a “Heizlokomotive” (heating locomotive).
Old steam locomotives were often used for preheating carriages, or as switch heaters to prevent them from freezing in winter. Heating locomotives were also used as heat suppliers to heat the premises of the railway depots.
If a steam locomotive was only intended to be used as a heating locomotive, only a simplified overhaul was carried out. In many locomotives, the preheater was shut down and replaced by a second jet pump . Only the components required for heating, such as the boiler, were given a full inspection.
Photos of heating locomotives show high chimneys were often placed on the original locomotive chimney to improve the draft and to divert the smoke. In the case of rolling locomotives, this elevation was apparently usually mounted on a frame under which the locomotive could be driven or pulled out.
And the Deutsche Reichsbahn classifications of these steam locomotives.
Heizlok (heating locomotive)
A fully operational locomotive that was used for limited traction.
Provisorische mobile Heizanlage (temporary mobile heating system)
A decommissioned steam locomotive, whose boiler was kept in working order. In the repair shop they were equipped with appropriate steam extraction connections for heating service. These locomotives were allowed to travel under their own power between the heating location and the depot with a special permit to resupply themselves or to change their heating location.
Locomotives were delivered to the depot almost complete, along with their removed parts. With relatively little effort, it would have been possible to restore them for operational service. As As result many traditional Deutsche Reichsbahn locomotives “survived” in this way.
Some locomotives of the DRG Class 44 lost their entire internal drive in the Meiningen repair shop without the remaining parts being adapted for two-cylinder operation. After that, due to the disturbed mass balance, they were only allowed to travel at 60 km/h, tow a trailer load of 60 tonnes and were also acoustically recognisable due to the missing third exhaust beat.
Dampfspender (Steam dispenser)
This was the name given to stationary, decommissioned locomotives with a boiler that was still usable. Everything that was not necessary for generating steam or that could be used as a spare part for other locomotives was removed from these locomotives.
The engine was dismantled (cylinders, connecting rods, brakes) and the chassis was often simplified by removing individual axles. The axles in the area of the firebox were removed in some cases to make it easier to access the ash pan from the side. With the wheel sets removed, such a locomotive cannot roll.
“Trafostations” in the age of electricity
As steam locomotive gave way to electric traction, so did the method of carriage heating – “Zugsammelschiene” (head-end power) was introduced, with electric heaters in each carriage powered by a transformer in the electric locomotive hauling the train. However the problem of preheating carriages without a locomotive was still a problem, so retired electric locomotives were converted into “Trafostations” (transformer stations).
Again, German-language Wikipedia has the backstory.
As with the steam heating locomotives, parts that were not required for their new role as a carriage heating power supply were removed from decommissioned locomotives. The electrical supply to these transformer stations was often via fixed wires instead of the pantographs, and in some cases, the former locomotives were placed away from the station on sections of track specially laid for this purpose .
In addition to supplying power to parked passenger trains, transformer stations were used for other purposes, such as in winter for electric point heaters where such heaters were available. Often the heating of the points had previously been converted from propane gas to electricity . Another use was to provide electricity for testing purposes in repair shops; for example, the two former locomotives in Frankfurt am Main shown opposite served this purpose .
The electric heating locomotives used included several examples of the DRG Class E 04, DRG Class E 52, ÖBB Class 1020 and ÖBB Class 1670.
Many former heating locomotives and transformer stations were not scrapped after being taken out of service, but were preserved as museum exhibits. Most of them were at least refurbished externally.
Some newer examples trafostations remaining in use through the 2010s, like this ÖBB Class 1042.
And today
As you might expect, keeping an old electric locomotive around just for the transformer inside it is a lot of work – so instead they installed special power outlets – “zugvorheizanlage” (train preheating systems) – at carriage yards.
Again, from German-language Wikipedia.
The electrical energy is taken either from the railway power supply network or from the public medium-voltage network and fed to the transformer via a medium-voltage switchgear consisting of a isolator (e.g. an overhead line switch ) and a circuit breaker . The transformer supplies a busbar with the voltage required by the train.
The power per branch in common systems is up to 800 kVA . When fed from the public grid, the maximum power depends on this, since the single-phase train busbar common in the UIC places an asymmetrical load on the public three-phase grid.
Each outlet leads from the switchgear house to a heating element. This usually consists of three units: the control column, a predetermined breaking point and a dummy socket stand.
The predetermined breaking point prevents major damage to the system if the train is accidentally moved despite the cable being connected. It is designed so that the heating cable can be torn off by the moving train without causing damage to the stationary system that is difficult to repair. It usually works in such a way that the end of the flexible heating cable is pulled straight out of the connection point through guides.
The dummy socket stand is used to hold the electrical jumper cable when it is not connected to a train.
