SSB ZT 4
| SSB ZT 4 | |
|---|---|
 SSB ZT 4
|
|
| Numbering: | 1001-1003 |
| Number: | 3 |
| Manufacturer: | Maschinenfabrik Augsburg - Nürnberg (MAN) (mechanical part, car body), Schweizerische Lokomotiv- und Maschinenfabrik Winterthur (SLM) (bogies), Allgemeine Elektricitäts-Gesellschaft (AEG) (electrical equipment) |
| Year of construction (s): | 1982 |
| Axis formula : | (1z1) ´ (1z1) ´ (gear on the valley side, non-drive axis) |
| Gauge : | 1000 mm ( meter gauge ) |
| Length over coupling: | 20,105 mm |
| Height: | 3715 mm |
| Width: | 2650 mm |
| Smallest bef. Radius: | 60 m |
| Empty mass: | 33 t |
| Top speed: | 30 km / h, can be reduced to 21 km / h when going downhill |
| Continuous output : | 2 × 263 kW |
| Gear system : | Riggenbach |
| Power system : | 750 V DC |
| Power transmission: | Overhead line |
| Coupling type: | Scharfenberg coupling |
| Seats: | 56 |
| Standing room: | 56 (4 P / m²) |
| Floor height: | 1005 mm |
The ZT 4 is a locomotive of the Stuttgarter Straßenbahnen (SSB), which has been used on the Stuttgart cog railway since 1982 . The designation "ZT 4" stands for rack-and-pinion railcars with four axles. The track width of the ZT 4 is 1000 millimeters ( meter gauge ), the gear drive is designed for a single-lamellar, ladder-shaped rack according to the Riggenbach system in the center of the track and at the same height as the top edge of the rail. The ZT 4 has replaced the previous generations of vehicles on the Stuttgart rack railway.
prehistory
In the 1970s, the Stuttgart rack railway and its rolling stock were in a critical and desolate condition. Apart from a few changes and the new Upper Weinsteig Bridge, the line had practically not been rehabilitated since it was converted to electrical operation in 1902. The operation was five part 40-year-old railcars (Nos. 101-105) and five Vorstellwagen conducted from the steam railroad period of the late 19th century (Nos. 116-120). The old age of the vehicles , most of which had run well over a million kilometers, and the increasing shortage of spare parts led to ever shorter maintenance intervals for electrical and mechanical parts and ever more frequent breakdowns. In 1974, railcar number 102 had to be abandoned and dismantled. Last but not least, the vehicles caused considerable noise and were no longer up-to-date in terms of equipment and driving comfort.
In addition, there were aggravating legal and economic problems: according to the tram construction and operating regulations (BOStrab), the use of wagons with wooden superstructures was only permitted with an exception permit , a desirable automation of the doors or a locking of the platforms would not or only be possible with the presentation wagons disproportionately high effort was possible. But even with automatic doors and the possible omission of the conductor, one could not have done without a responsible brakeman for the introductory cars, since the driver could not see the route from the railcar on the valley side.
For its part, the SSB suffered from the economic situation and the still growing competition from private transport and was thus forced to pursue a systematic austerity policy, which is why it sought more cost-effective one-man operation on all lines. In 1978 it therefore decided to procure new, larger railcars with the capacity of a previous train and thus to finally forego the use of front cars.
development
The ZT 4 was commissioned by the SSB in 1979 almost at the same time as the first three light rail prototypes . Since the MAN company was responsible for the construction and the mechanical part of both vehicle types, it made sense to use the knowledge gained from the development of light rail vehicles for the purpose of standardizing the vehicle fleet. The vehicle has the outer shape and appearance of a halved DT 8 according to the design of the Lindinger & Partner design office, but with two driver's cabs, the interior division was based on the scheme of prototypes 1 and 3, which was later adopted for the light rail series vehicles The “by-product” of the light rail car is a pleasing four-axle solo multiple unit that is adapted to requirements. Since the rack railway was not designed as a tram route from the beginning , but as a railway with appropriately sized vehicles, the supposed excess width of the meter gauge wagons of 2.65 meters hardly had a disadvantageous effect.
technology
drive
The S-ZT 4 is driven by two mixed-current series motors transversely to the direction of travel via a gear unit only on the drive gear, which is located on the respective valley-side axle of a bogie (for more details see special features). The bogies come from the Swiss Lokomotiv- und Maschinenfabrik Winterthur (SLM) and do not have a pivot. The car body is supported by two rubber-metal layer springs as cross members, the longitudinal forces are taken over by external trailing arms.
To simplify maintenance and to shorten downtimes, SSB also procured an additional reserve bogie. One of the bogies is usually always serviced in the main workshop of the SSB and installed alternately in the three cars. Usually every week the vehicle deployment changes by one car.
Braking systems
The S-ZT 4 has three independent brake systems. The regenerative resistance brake serves as the main and service brake, which enables the braking energy to be fed back into the line network when a consumer is present. This is usually the second car used. In addition, the catenary of the cog railway serves to balance the performance between the cross-valley lines (Degerloch) and the longitudinal lines (Marienplatz) of the Stuttgart Stadtbahn, so that there is an electricity network. There are also two mechanical spring-loaded brakes ( ratchet brake and gear brake, both hydraulic spring-loaded brakes), which are manually operated by the driver in the lower speed ranges. One of them is designed as a ratchet brake to prevent reverse movement when driving uphill. The function is similar to a combination of a centrifugal governor and a coaster brake , as you know it from a bicycle. Typical of the ratchet brake when driving uphill is the clicking sound of the detents in the brake drum, where they slide along a mechanical backdrop. When driving downhill, on the other hand, the locking lugs spread so far away from their axis due to the rotation of the wheels that they rotate in the air space of the drum without hitting. If the speed would exceed a certain level downhill, the detents would touch the backdrop and intervene there. The vehicle would then be brought to a standstill if it were softened by an oil damper. The actual braking effect occurs through the mechanical friction brake on the main gears. When driving uphill, the downhill force is always used to stop; here the mechanical brake only serves as a parking brake.
Specialty
problem
So that rail vehicles can achieve the geometrically ideal sinusoidal run on the track with a normal friction track, wheels and axle shafts are usually firmly connected to one another, called a wheel set . In the track curves this leads to the slight interval-like sliding of the respective wheel ("slip"), but is accepted because of the advantages in the straight track. In the case of a rack-and-pinion railway vehicle, there would be constant slippage even in a straight line because the diameter of the running wheels would decrease due to wear, while the diameter of the gear wheel always remains exactly the same. Because the gear only wears on the valley-side flanks of the teeth, not at their tips. The result would be that the impeller would almost never have the same speed around the circumference as the gear. The further consequence would be an extremely high level of wear on the surface of running wheels and rails.
solution
To get around this, the main gear (pinion) sits loosely on the axle shaft. In this way, the rotation of the main gear is exactly synchronized with the rack, without any irritation from the running wheels. All wheel sets and running wheels of the car therefore run without a drive. As a result, it is also possible to drive through the curved track without jerking, which increases the feeling of security on a cog railway.
The main pinion is also resiliently arranged on the axle shaft. Unevenness in the track, vibrations in the running of the vehicle or fluctuations in the car body, for example when there is a heavy rush of passengers, are not transmitted to the main pinion. As a result, the pinion constantly grips the rack with a constant depth, which is important for the even power transmission and surface loading of the teeth. Only the two main pinions are used to drive and brake. With the steep incline of the rack railway, drive or braking via the running wheels would be of no importance. The axle shaft only serves as an abutment for the main pinion, in which the gear of the drive motor engages. The brakes also act on the main pinion, not on the axle shaft or the wheels. The running wheels are used to guide the car on the track in the usual way. The rack has no leading function, it only transmits the pressure forces. Because of the safety and the more even distribution of forces, each locomotive in a rack railway has two main pinions.
Furnishing
The ZT 4 has 56 seats and just as many standing places, the interior layout corresponds to that of the DT8 with two separate, partially glazed driver's cabins, two double-leaf doors on both sides and arrangement of the seat backs at the height of the window bars. The ZT 4 is also a high-floor vehicle with a floor height of 1005 millimeters, but the difference in height must be overcome by means of three built-in steps in the door areas. The original color scheme differed from both the series DT 8 and the prototypes: green seat cushions were combined with yellow handrails and a brown-checked textile carpet floor; the outside of the car was black in the lower area, cadmium yellow on the sides and anthracite on the window area and roof painted.
The line and destination signage was carried out by means of roller bands on the front sides, there was no need for side signage and an inner pearl band display as with the DT 8.
Use and gradual modernization
In order to be able to use the ZT 4 on the Stuttgart rack railway, it had to be completely modernized beforehand. It was therefore closed for eight weeks from July 24th to September 7th, 1980, during which time omnibuses took over. If not already there, an independent track structure was laid, the substructure reinforced, a new central platform built at the Wielandshöhe siding, the romantic but underperforming double contact line on the historic curved masts replaced by a modern catenary cable and a new, longer transfer platform to the depot built-in. The historic cog railway station on Filderstraße was redesigned to a modern storage hall for two ZT 4s, the third was located on the upgraded platform 3 of the southern wagon hall. The workshop halls on the northeast side were abandoned, and the Rampe theater moved here a few years later .
The first ZT 4 with the number 1001 arrived on August 3, 1982 at the Degerloch cogwheel station . After several of the old wagons sold had been removed on August 23, 1982, thus creating space, the 1002 railcar was delivered to the rack railway, also in Degerloch, on August 27, 1982. With great public interest, the new vehicles were towed from the historic motor coaches 103 or 101 and 104 to the Marienplatz depot. The technical acceptance of the wagons was carried out by the Federal Office of Transport (BAV) in accordance with Swiss safety regulations, as there were no corresponding regulations in Germany. Immediately afterwards, the test drives began, and on September 11 and 12, 1982, the cars were presented to the public as part of a “Zacke Festival”.
On October 23, 1982, TW 1003 followed. Since then, they gradually took over the planned traffic on the cogwheel railway line, but due to initial unforeseen difficulties, the motor car 105 intended for sale had to be kept as an operating reserve until the end of 1983. At the anniversary celebrations in 1984, the remaining museum railcar 104 suffered irreparable damage to the winding insulation of the motor on the mountain side due to switching overvoltage, so that since then only the ZT 4 and the bicycle sidecars that have since been delivered have been used on the route.
The ZT 4 nos. 1001 and 1002 have been named " Heslach " and " Degerloch " since the 1980s , car 1003 was named " Helene " (after the Degerloch citizen Helene Pfleiderer ) in 1995 .
As of 1989, the first major renovation was gradually replaced by the fault-prone electric swinging sliding doors with compressed air-powered outward swinging doors made of plastic, like those used in the DT 8.
From 2000 onwards, the wagons were thoroughly modernized one after the other, which meant that at times only one train could run on the route every half hour. The first railcar to be used was the TW 1001 in this new guise from February 2001, with the color scheme, which is now based on the DT 8.10 light rail vehicle type, with the car body painted in gorse yellow and night blue ribbon windows. In addition, the carpeting was replaced by a synthetic floor covering like the one on the light rail, and the vehicle technology was modernized, among other things, with electronic drive control and the installation of the ZUB train control system and the IBIS on- board information system as well as the installation of a tachograph .
After appropriate renovation of the other two railcars, further changes followed in the course of workshop visits: The ZT 4, like the DT 8.4-9 trams, received two-part, blue seat cushions; In the autumn of 2008, the conveyor belts for line numbers and destination signs were finally replaced by LED displays.
Car 1001
Car 1002
Car 1003
outlook
Currently (2015) these vehicles have been in use for over 30 years and are nearing the end of their economic life. In addition, they are not barrier-free. In 2018, the SSB ordered three rack and pinion railcars from the Swiss manufacturer Stadler , which are to be used from 2021. The stops will be converted for barrier-free access to the new vehicles.
literature
- Over mountain and valley - news sheet of the Stuttgarter Straßenbahnen AG / Stuttgarter Straßenbahnen AG (ed.)
- Ulrich Theurer: 100 years of the Stuttgart – Degerloch cog railway
- Dirk v. Harlem: New rack-and-pinion railcars for Stuttgart - technical description
- Tram magazine, issue 53, August 1984, p. 163 ff. Franckh'sche Verlagshandlung Stuttgart, ISSN 0340-7071
- Gottfried Bauer: Tram in Stuttgart, "Over mountain and valley with the SSB", GeraMond Verlag, Munich 2003, ISBN 3-7654-7188-7
- G. Bauer, U. Theurer, C. Jeanmaire: Trams around Stuttgart, FBG, CSB, ESS, END, SSF. Verlag Eisenbahn 1984, ISBN 3-85649-047-7
- Gottfried Bauer, Ulrich Theurer: From the tram to the Stuttgart city railway 1975–2000 . Stuttgarter Straßenbahnen AG, Stuttgart 2000, ISBN 3-00-006615-2 .
- Knupfer, H.-J .: The train to the beautiful view - Stuttgart's rack railway. Stuttgart 2009, ISBN 978-3-9811082-2-4
Web links
- Official website of the Stuttgarter Straßenbahnen AG, which u. a. the Stuttgart rack railway, which operates the rail cable car (funicular) in Stuttgart-Heslach: www.ssb-ag.de
- Rack railway Stuttgart ( Memento from December 20, 2005 in the Internet Archive )
- Details of all locomotives
- Collection thread for the possible restoration of the historic TW 104 in the Bahnforum Stuttgart
Individual evidence
- ↑ Konstantin Schwarz: Stuttgart is getting a new point. In: Stuttgarter Zeitung. December 11, 2018, accessed December 11, 2018 .