DB class 725/726 - DB-Baureihe 725/726
|DB class 725/726|
|725 series||726 series|
|Gauge||1435 mm (Normalspur)|
|Leather massage||20 t||17 t|
|Allowable mass||28 t||18 t|
|Length over buffers||13.950 mm||13.400 mm|
|Driving wheel diameter||900 mm||-|
|Impeller diameter||-||850 mm|
|Coupling type||Screw coupling at the end of the unit; There is a Scharfenberg coupling between the cars|
|Top speed||90 km / h|
|Number of engines||2||-|
|power||2 × 110 kW||-|
|Brake type||KE-P (D)||KE-PA (D)|
|Tank capacity||360 l||-|
Conversions of Uerdingen rail buses |
into motor vehicles for the track measurement train 
|converted vehicle||original vehicle|
|725 001-2||798 804-2|
|725 002-0||798 676-3|
|725 003-8||798 779-5|
|725 004-6||798 674-8|
|725 005-3||798 799-3|
In the 1970s, the number of track measuring cars on the Deutsche Bundesbahn was low, and the maximum speed of the vehicles used was too low.  Therefore, the developed Bundesbahn Central Offices Munich a novel Gleismesszug . In 1974 five trains were put into operation, each consisting of a measuring car and a railcar and which are permanently coupled in this configuration. While the railcars of series 725 AW Kassel converted railcars of series 798 represent, the at Messerschmitt-Bolkow-Blohm in Donauwörth newly built and measurement technologyMatisa equipped measuring car called the 726 series.
Since every route is checked at regular intervals, it was stationed at locations that were spread across the whole of Germany: In 2002, for example, these were Ingolstadt , Nuremberg , Braunschweig , Darmstadt and Cologne-Deutzerfeld . In 2011, four of these track measuring multiple units were still in use at DB after train 725/726 001 was retired in December 1999.   In November 2012, train 725/726 005 was retired; after the shutdown of train 725/726 004 shortly afterwards, the number of units in operation fell to two. The unit 725/726 004 is now back in use. The trains are now part of the DB Netz Maintenance division and are based in Minden .
The Münchner Verkehrsgesellschaft rents a series 726 measuring vehicle to check the rail network of the Munich subway at regular intervals . Since the gauge and clearance profile of the Munich subway match the corresponding parameters on German mainline lines , it can also be used in subway tunnels. Only the 726 series measuring car is used; a battery locomotive from the Munich transport company takes over the drive. Since the generator for the power supply of the measurement technology is also installed in the 725 series, an additional car with a diesel generator is required for power supply when used in the subway.
Car body and body
The car bodies of both cars were designed as a welded frame with sheet steel cladding. The car body of the 726 series corresponds to that of the 701 series , which is why the structure is higher than that of the 725 series. The 726 series car body is provided with particularly torsion-resistant longitudinal and transverse members to prevent creeping falsification of the measurement results due to twisting of the frame.
The chassis of both cars were welded. Normal side buffers and screw couplings were attached to the ends of the chassis . The screw couplings between the cars were later replaced by Scharfenberg couplings .
The car bodies of the 725 series are cushioned with air suspension, which was adopted unchanged from the Uerdingen rail buses. The vehicles of the 726 series, in which the measurement technology is housed, have a special suspension to keep the wagon always horizontal and at a constant height above the upper edge of the rail, regardless of its load and the route of the route. This is necessary to ensure sufficient accuracy of the measurement results.
The carriages are braked by a multi-release Knorr disc brake of type KE.
Two are for driving a unit driving motors of the type Bussing U10 available. This diesel engine has six cylinders and transmits its torque via a hydraulic clutch and an electromechanical gearbox to the remote axle. Between the transmission and the Radsatzwendegetriebe are drive shafts available.
Three windows were removed on both sides of the 725 series motor vehicles and the noise level in the interior was reduced, and a driver's cab in the motor vehicle was also removed. In the interior there are two sleeping compartments, a washroom and a lounge with a stove and refrigerator. A water tank with a capacity of 200 liters was installed on the roof. The interior also houses a machine room, which houses a diesel generator set to supply the measuring devices of the measuring vehicle with power.
A workbench for small repairs has been set up in the measuring car 726. Some spare parts are carried as standard. The safety technology for punctual train control is housed in a cabinet behind the driver's cab . The measuring van also has a work station with a computer and a printer. There is an intercom to communicate with the crews in the two parts of the track measuring multiple unit, between which there is no transition . The electrical energy requirement of these components is covered by a generator installed on an axle, while the measuring devices of the 726 series are fed by the diesel generator in the 725 series.
Three axles, which were attached under the car body, accommodate the measuring devices. These register the track parameters in order to display them on a measuring table. This mechanical measurement technology is now considered obsolete, as digital measurement devices using ultrasonic testing or laser technology achieve greater accuracy and can be operated at higher speeds, while the measurement speed of the 725/726 series is limited to 80 km / h.
- Michael Dostal: DB vehicles: locomotives and railcars of the DB AG . GeraMond-Verlag, Munich 2002, ISBN 3-7654-7175-5 , pp. 186f.
- Technical data for the 725/726 series at bahnstatistik.de
- Description and pictures of the use on eisenbahndienstfahrzeuge.de
- Photos of the track measuring multiple units on bahnbilder.de
- Description and pictures from the deployment on eisenbahndienstfahrzeuge.de , accessed on July 29, 2013.
- Michael Dostal: German railcars - Deutsche Bahn and private railways. GeraMond, Munich 2011, ISBN 978-3-86245-113-5 , pp. 138f.
- DB class 725/726 on amgbo.eu , accessed on July 30, 2013.
- Class 725 ⁄ 726 - track measuring multiple units on sauerlandbahnen.de , accessed on July 30, 2013.
- Gleismesszug DB on u-bahn-muenchen.de , accessed on 13 December 2016th
- DB track measurement train GMTZ in Luxembourg on rail.lu , accessed on July 30, 2013.