Lock stairs Niederfinow
| Lock stairs Niederfinow | ||
|---|---|---|
 Lock III of the Niederfinow lock staircase, March 2009 |
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| location | ||
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| Coordinates | 52 ° 51 '6 " N , 13 ° 56' 10" E | |
| Place: | Niederfinow | |
| Waters: | Havel-Oder waterway | |
| Data | ||
| Start of operation: | 1914 | |
| Shutdown: | 1972 | |
| lock | ||
| Type: | Inland lock | |
| Usable length: | 67 m each | |
| Usable width: | each 10 m | |
| Average height of fall : |
9 m each | |
| Upper gate: | Miter gate | |
| Lower gate: | Miter gate | |
| Others | ||
The four-step Niederfinow lock staircase in the north of the Barnim district in Brandenburg was the oldest lock structure at the eastern end of the apex in the Oder-Havel Canal . The western end is the Lehnitz lock near Oranienburg . The staircase was in operation from 1912 to 1972. In 1934, the Niederfinow ship lift went into operation in parallel. The latter will be shut down by 2025 at the latest and replaced by the larger Niederfinow Nord ship lift, which is currently under construction .
The locks
The total fall height of 36 m was overcome by four chamber locks with exactly the same construction except for the foundation (9 m each). Each lock had a usable chamber length of 67 m and a clear width of 10 m, which enabled it to be used by ships up to 600 t. All locks were as saving locks built, that is, on both sides of each lock basin three per saving basins were connected, the (equivalent to 3.58 m drop height) the water loss in the smuggling to 40% reduced. Upper and lower gates were stem gates .
The chamber walls are 8 m wide at the bottom and taper towards the top. The chamber soles with a thickness of 1.20 to 2 m are made of concrete with iron reinforcement. The locks were surrounded with iron sheet pile walls that extend up to 16 m into the ground. Locks I, II and III are on natural ground. Lock IV (the lowest lock) is in the moor , which is up to 5.5 m thick. It was excavated by lowering the groundwater and the chamber walls were founded on a pile brush of 2000 piles. The saving pools stand on silted up sandy soil .
For the operation of the locks, circulation channels with a large cross-section are built into the two chamber walls , which have their inlet in front of the upper gates and open below the lower gates. Twelve smaller branch channels each branch off from these circulation channels to the lock chamber and three side channels each for the three savings basins on the corresponding side. The circulation channels were closed at the top by cylinder valves and at the bottom by segment gates. While the branch channels to the lock chamber are open, the side channels again had cylinder valves . All movement devices were powered electrically, and could also be operated manually in the event of a power failure. For inspection purposes , the entire system of the lock staircase could be completely emptied with the help of a needle weir in the Oberhafen.
The entire system and the lock process
In order to be able to use the lock staircase from both directions at the same time, there is a 260 m long section of canal between the individual locks, a so-called intermediate stop , where the ships going up and down could meet. A system of locks with intermediate holding is also called a compound lock . The long distance of the intermediate holding ensures only slight fluctuations in the water level when the water is drained from the higher-lying lock.
When the canal was being built, it was common to have tow trains whose barges did not have their own drive . But as they are funneled individually had, they were along the intermediate positions with the aid of electric locomotives , the inverted both sides of the intermediate positions, towed . To this end, 8 tow locomotives were delivered by the Siemens-Schuckert works in 1914 . Six were used for the constant towing operation on the lock stairs, two were available as reserves. These locomotives had an operating weight of around 12 tons and a pulling force of max. 1500 kg. Both axles of the locomotives were driven by a motor with a double back gear. The motors had an output of 4.5 hp at 500 revolutions per minute and a voltage of 550 volts. A third motor drove the rope drum. The direction of rotation and speed of the motors were controlled by shifting the brushes. The locomotives had a top speed of around 9 km / h, a track width of 1000 mm and a 2 m wheelbase. The overhead line was installed 5 m above the top of the rails. The smallest curve of the track was 15 m in the area of the lock bridge. After the ship lift opened in 1934, two identical locomotives were delivered. The towing traffic on the lock staircase was discontinued when it was shut down in 1972 and, due to the suspension of tug traffic on the Oder-Havel Canal, also at the ship lift. It took twelve minutes to drive through an intermediate stop, including entering and exiting the lock. The axes of the locks are offset by 10 m to make it easier for ships to meet in the intermediate stops .
Filling and emptying a lock each took nine minutes (one meter per minute). In addition to the towing times, it took about an hour and a half to go through the entire staircase.
Despite the precautions taken to save water, the sharp rise in shipping traffic resulted in excessive water consumption. In addition, the long transit time was a hindrance. Therefore, the planned ship lift was built between 1927 and 1934. The locks remained in operation, but were used less and less after the war and finally closed in 1972. The lock staircase thus fulfilled its task for 58 years.
Construction features, data and costs
The later construction of a ship lift for the lock staircase was already included in the planning. On maps and aerial photographs it can be clearly seen that the canal to the lock staircase branches off to the side, but the position of the ship's lift corresponds exactly to the direction of the canal.
A total of 600,000 cubic meters of earth were excavated along a straight line between the Barnim plateau and the Oder valley
The construction material required:
- 20,000 tons of cement
- 4 million bricks
- 6,000 tons of trass
- 70,000 cubic meters of gravel
- 20,000 falling rocks
- 6,000 cubic meters of paving stones for the intermediate supports
- 500 tons of iron reinforcement for the concrete
- 2,200 tons of iron sheet piling
- 500 tons of iron for the cylinder shooters
- 175 tons of iron for the lower gates
- 80 tons of iron for the upper gates
(at that time steel was still called iron)
The construction of each lock cost around 1.5 million Reichsmarks , so the entire system around 6 million Reichsmarks.
Today's condition and current changes
At the head of Lock I, the canal was blocked off and sealed with concrete pillars . All locks and savings basins are therefore empty; Some seepage water flows in the intermediate stops . Some parts were dismantled for scrap extraction . The entire facility is no longer open to the public. Where you can still reach the area, there is a risk of falling into the empty pools. The closest you can get to the best-preserved lock I from the parking lot (Landstraße Eberswalde - Liepe ). The whole area, especially of course the intermediate stops, is overgrown. The formerly public path on the north side, which is still accessible, runs on the old tow line . You can still see thresholds made of wood, steel and concrete.
The new Niederfinow Nord boat lift is being built between the old boat lift and the lowest section of the lock staircase. The most drastic changes to the listed facility are the backfilling of lock III and the partial demolition of lock IV. Only the two lock heads remain, the lock chamber and savings basin are filled in. The access road to the new ship lift will lead through the lock. The intermediate holding between locks III and IV will be partially filled. This is where the Liepe-Niederfinow road runs along.
See also
Web links
- Historical photos of the lock stairs on oder-havel-kanal.de
swell
- Rudolf Schmidt , commemorative publication for the opening of the Hohenzollern Canal (Eberswalde 1914)
- schiffshebewerkndf.de
- Historic hydraulic structures in northeast Germany