A Bahnbetriebswerk (also abbreviated to Betriebswerk, Bw or BW) is a German railway depot where the maintenance of locomotives and other rolling stock is carried out. It is roughly equivalent to a locomotive shed, running shed or motive power depot. These were of great importance during the steam locomotive era to ensure the smooth running of locomotive-hauled services. Bahnbetriebswerke had a large number of facilities in order to be able to carry out their various maintenance tasks. As a result, they needed a lot of staff and were often the largest employers in the area.
The history and present-day importance of such depots is covered in the Bahnbetriebswerk article.
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Functions Preparation of engines
Before a steam locomotive was allowed onto the line, the crew had to carry out a large number of preparatory jobs. In accordance with the enginemen roster, the locomotive crew – engine driver and fireman – reported to the running foreman of the Betriebswerk in question. There they were given the key to their locomotive, a repair book, a route plan and timetable and a list of the trackworks en route. After completing all the formalities, the engine driver and fireman went to their engine, which was either berthed in the locomotive shed or stabled on a siding. After climbing into the driver's cab, the engine driver began with the most important checks: regulator, valve seals, water levels and a brake test. The fireman checked the equipment on board and the fuel supplies. Not until these checks had been carried out did the crew begin their actual work.
The fireman began by lighting the fire in the locomotive, then driving it to an inspection pit. Whilst the engine driver looked underneath the engine for any damage, the fireman - equipped with oil can and grease gun - had to service all the grease points on the locomotive (see photograph).
Once all the checks had been carried out and the boiler had reached its operating pressure, the locomotive could drive out of the shed and onto the turntable. After the tracks had been cleared by the signal box, the locomotive officially began its duties and ran out onto the main line.Beruf Lokführer, pp 57–71.
Disposal of engines
During the final kilometres to the terminal station the fireman began to prepare for disposal (Abrüsten) by letting the fire slowly burn down depending on demands of the route. After the train had arrived at the terminus, the fireman turned off the train heating and the locomotive was uncoupled from the wagons. Then the locomotive was returned to the Betriebswerk, where it first went to the coaling plant, where its coal was replenished. Next the engine proceeded to the ashpit where the boiler was cleaned out by the shed workers (Betriebsarbeiter). This involved emptying the ash and clinker from the smokebox and grate into an ashpit sunk between the tracks. This was a particularly dirty job. After completely cleaning out the boiler the engine was run to the water cranes, where the engine's water tanks were refilled. The next stop was the sanding point. At smaller Betriebswerke, refilling the sanders was manual work using buckets and ladders.
Because the locomotive was now fully equipped with everything it needed for its next duty, it was either stabled in the locomotive shed or on a spare stabling road and cleaned further by the fireman. Repairs were dealt with by the staff responsible for them during the night. Afterwards the engine was prepared for its next duty.
Washing out
The boiler of a steam locomotive had to be cleaned at regular intervals. This took place in the Bahnbetriebswerk at laid down times. The interval between boiler washouts varied according to the quality of the boiler feedwater, the frequency of runs and the demands of the routes being worked on the locomotive. The washing out of a steam locomotive boiler consisted in six stages of work:
First the boiler had to be blown down. After it had cooled, the water was drained. Once this was completed, the cleaning of the boiler could begin. After that the boiler was refilled and heated up again.
When a locomotive was due for boiler cleaning, preparations for washing out were started even whilst the locomotive was on its final run beforehand.
Routine examinations and scheduled repair work
Whilst the shed hands were busy washing out a locomotive, fitters carried out routine examinations and scheduled repair tasks. This work was necessary in order to keep the engine operational for as long as possible between general inspections. In order to keep stoppages of locomotives to a minimum this work was distributed throughout the year. Amongst the most important tasks were the biannual brake system checks, the quarterly condition examinations and a yearly main brake inspection. Special tasks are detailed in the following table.
JobIntervalTest brakesno more than 4 daysTest service brakedailyClean sandersno more than 4 daysGrease axle boxesno more than 4 daysCheck oil oiling pointsno more than 4 daysCheck central lubricating systemno more than 4 daysClean trailing box and check oil pipesno more than 4 daysOil Schlingerkeile and outer firebox supports no more than 4 daysCheck small suspension rods and compensating lever dailyGrease brake linkages, clean oil ductsno more than 4 daysGrease connecting rod bearingsno more than 4 daysCheck glides and hinge boltsdailyCheck valve gearno more than 4 daysCheck wheel flange greasingno more than 4 days Job IntervalCheck tools and implementsno more than 4 daysCheck boiler feedwater equipmentno more than 4 daysCheck drainage valvesno more than 4 daysCheck steam and hot water pipesno more than 4 daysCheck fireboxdailyCheck water level gaugesdailyCheck sludge removal equipmentdailyCheck boiler safety valvesdailyCheck ash pan and smokebox sprayerno more than 4 daysCheck chimney (Rauchfänger) and spark arrestordailyCarry out basic seal checksno more than 4 daysCheck the small suspension rods, bogie pins, suspension springs, axleboxes and greasing points on the tenderno more than 4 daysCheck connecting rods and coupling rods180 days
Special duty trains
In addition to the maintenance of all locomotives, some Bahnbetriebswerke are also responsible for looking after special duty trains. The most important units are breakdown trains (for re-railing derailed rolling stock) and rotary snow ploughs. There are also fire fighting trains to enable fires in the area to be put out as quickly as possible. And for the smooth running of a Bahnbetriebswerk tractors and shunters are needed in order to move wagons and locomotives that are unable to move under their own power. Finally almost every Bahnbetriebswerk has a variety of special vehicles.
Facilities
Key: 1 - Water crane, 2 - Coaling point, 3 - Signal box, 4 - Roundhouse, 5 - Locomotive repair shop, 6 - Washout equipment, 7 - Inspection pit, 8 - Turntable.
Operating facilities
The maintenance of a steam locomotive requires a large number of different facilities.
Water points
The running of steam locomotives required water as well as coal. As a result, the water supply of a Betriebswerk played an important role. In order to guarantee the supply, almost all Bahnbetriebswerk had their own railway waterworks. These waterworks were equipped with various systems for delivering water (pumps, pipes, water containers and take-off points). Many Bahnbetriebswerke had two different waterworks: one railway waterworks that provided water for the engines and a drinking waterworks that supplied water for the employees of the depot. When Betriebswerke were eventually connected to the regional water network, their drinking waterworks was usually closed down. The water was extracted from springs, wells and ponds and then cleaned. Industrial water for the running the steam locomotives had to have a high level of quality. As a result, the railway waterworks developed their own filtering systems, where the water for operations was made usable. Especially important were the salt content and the hardness of the water.
After cleaning, the industrial water was pumped into a water tower and drawn from there. These facilities had various designs; there was no standard type. All water towers had several up and down pipes. The water towers supplied all areas with industrial water, including the water cranes used to replenish the water supplies of steam locomotives (whether they had tenders or water tanks). Water cranes were usually located near the inspection pits or at coaling points. They, too, came in various shapes and sizes, although these were gradually replaced by standard types of water crane.
Large and medium-sized Bahnbetriebswerke had their own laboratory that continuously monitored the water processing; in particularly checking the preparation of the boiler feedwater which was tested regularly. The laboratory specified the salt content, the pH value and the composition of the feedwater. The enginemen had to bring samples of feedwater to the laboratory at specified intervals. In addition to testing the water, the laboratory was also responsible for checking oils and greases delivered to the depot.
Locomotive sheds
Every large Betriebswerk had its own roundhouse with a turntable. The locomotives were turned on the turntable and berthed in the roundhouse. This was heated so that the steam locomotives did not fully cool down, otherwise raising steam took too long. In order to move steam locomotives that were stored 'cold', locomotive winches were installed. It was prescribed by almost all railway companies that at least 75% of all locomotives had to be able to be berthed in the locomotive shed, the rest would be stabled on stabling roads in the open.
Large Betriebswerke often had two or three roundhouses with their associated turntables. The roundhouse was reliant on the turntable; if it became incapacitated the entire shed was out of commission because locomotives could not be run in or out of it. The turntable therefore had an emergency engine which used compressed air. Over the course of time, a standard turntable with a 26m long track was adopted. Turntables were always at the mercy of the weather and in very heavy use, so they had to be serviced at regular intervals. In fact every Bahnbetriebswerk with a turntable should also have had a triangle or wye, so that if the turntable was out of action, locomotives could still be turned. However, because wyes needed a lot of space they were only rarely built.
Smaller Betriebswerke often only had a parallel-road shed, which could be reached via turnouts. Every Bahnbetriebswerk had to have enough space in order that it could be extended in any direction. Smaller maintenance jobs were carried out in the locomotive shed itself. For more specialised repair or maintenance tasks there was usually an engine repair shop, most of which had an overhead crane with which heavy components could be moved.
Sanding points
Trouble-free locomotive running requires that there is sufficient traction between wheel and rail. Steam engines therefore had sandboxes (usually two, on top of the boiler). These were filled with the help of sanding equipment. For sanding there was either a sanding system with an elevated bunker or a sanding tower. The special sand was kept in its own store. On a sanding tower a telescopic pipe was hooked up to the sandbox, the lock released and the locomotive sandbox filled as required. All Betriebswerke had to have enough sand for at least 30 days.
Coaling points
Every Bahnbetriebswerk had one or more coaling points for the delivery and unloading of coal. In addition, they had to store the fuel and carry out the replenishment of locomotive coal tanks or tenders.