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     Dr.(Phys.)Dipl.-Ing.Ralf-Udo Hartmann

DB Deutsche Bahn AG

As Director of the research and development department of the technical attempt institution of the German federal railway ministry Minden i control 19 departmental managers with altogether 23000 employees in the Inter City Experimental ICE program. The Deutsche Bahn AG (or German Rail) is the provider of one of Europe’s most advanced and comfortable rail networks; a network which includes the high-speed ICE (Inter-City Express) trains used by 65,000 people every day in Germany and beyond.
 
 

The Deutsche Bundesbahn started a series of trials using the Inter-City-Experimental (also called ICE-V) test train. Pictures on the left i at the test run!

 
The IC Experimental was used as a showcase train and for high-speed trials, setting a new world speed record at 406.9 km/h (253 mph) on May 1, 1988. The train was retired in 1996 and replaced with a new trial unit, called the ICE S.
 
After extensive discussion between the Bundesbahn and the Ministry of Transport regarding onboard equipment, length and width of the train and the number of trainsets required, a first batch of 41 units was ordered in 1988. The order was extended to 60 units in 1990, with German reunification in mind. However, not all trains could be delivered in time. The ICE network was officially inaugurated on May 29, 1991 with several vehicles converging on the newly built station Kassel-Wilhelmshöhe from different directions.
 
 
The ICE1 and ICE2 trains look remarkably similar, but where the ICE1 has loco on both ends the ICE2 has one loco and one driving trailer.
 
Technical details:

-Builders:several German companies -ABB -AEG -Henschel -Krauss-Maffei -Krupp -Siemens
->Units built: 60
->Units in use: 59, one unit lost in accident
->Maximum design speed: 280 km/h (174 mph)
->Power: 9600 kW(2 x 4800 kW) (13 052 Hp)
->Electricity: 15 kV 16,7 Hz
->Unit numbers: 101 - 120, 152 - 190
->Loco unit numbers: 401 001 - 019, 051 - 090, 501- 520, 552 - 590
->Electrical systems: Asynchronous
->Unitlength: 410,7 m (with 14 cars)
->Height: 3,84 m, restaurantcar 4,3 m
->Width 3,02 m
->Windfactor: 0,17 at front, very low!
->Trailers: 14, 
->Couplers: Scharfenberg, including the connection within the train
-class 801: 1st class, 53 seats, 2 + 1 seating, toilet
-class 801.8: 1st class, 41 seats, telephone booth, toilet
-class 802: 2nd class, 71 seats, 2 toilets
-class 802.9: 2nd class (car 7), ?? seats
-class 803: servicecar, 35 second class seats, 2 wheelchair places, access free bathroom, baby chancing room, meetingroom
-class 804: restaurant car, places for40 seated customers and 10standing customers, the roof is higher on this car and has extra windows at the roof
 
 

These ICE trains have managed to slice hours off the journey times between popular destinations such as Hamburg in the far north of the country and Munich nestled in the south. Hamburg and Munich are just 6 hours apart whilst the journey from Hamburg to Frankfurt takes just 3 hours 30 minutes.


First introduced to the nation in the summer of 1991, the ICE trains have been connecting all of Germany’s major train destinations via high-speed train lines and at speeds of up to 175mph ever since. The ICE service operates primarily in Germany serving 32 destinations, though there are also some ICE rail links to Switzerland, Austria, Belgium, the Netherlands and France. It was in June 2007 that a new line was opened between Paris and Frankfurt/Stuttgart which is being jointly run by Deutsche Bahn and SNCF. ICE operates on the Paris - Frankfurt branch of the line and SNCF's TGV runs on the Paris - Frankfurt branch. At the end of 2007 there was a further development when the latest ICE trains were brought into service for the lines from Berlin to Århus and Copenhagen in Denmark.
 

As well as comprehensive catering facilities including on board restaurants serving hot food with proper crockery and restaurant seating, the ICE trains offer additional luxuries such as in-seat video screens (in first class), audio systems, and electrical sockets for laptops. Business people can also use the on-board fax machines and telephones.

The sleek red and white trains travel with practically no engine noise and with pressurized carriages preventing the ear-discomfort that can arise when traveling through tunnels. With the latest trains incorporating tilting technology, the top speeds of 175mph are likely to increase further, whilst maintaining the frequency and reliability of services that make train travel in Germany a real pleasure.
 

The ICE 1 is the first series of German high-speed trains and one of five in the InterCityExpress family. Revenue service at speeds up to 250 km/h started in 1991. It was raised to 280 km/h in May 1995 and later reduced to 250 again. Today, only a handful of ICE 1 services on the Nuremberg-Ingolstadt high-speed rail line reach 280 km/h.
 
Continuous train control

Linienzugbeeinflussung (or LZB) is a cab signalling and train protection system used on selected German and Austrian railway lines as well as the AVE in Spain. In Germany, the system is mandatory on all lines where trains exceed speeds of 160 km/h (200 km/h in Spain), but it is also used on some slower lines to increase capacity. The German Linienzugbeeinflussung translates to continuous train control, literally: linear train influencing. It is also called linienförmige Zugbeeinflussung.
 

The first prototype system was developed by German Federal Railways in conjunction with Siemens and tested in 1963. It was installed in Class 103 locomotives (pictures below) and presented in 1965 with 200 km/h runs on trains to the International Exhibition in Munich. From this Siemens developed the LZB 100 system and introduced it on the Munich-Augsburg-Donawörth and Hanover-Celle-Uelzen lines, all in Class 103 locomotives. The system was overlaid on the existing signal system. All trains would obey the standard signals, but LZB equipped trains could run faster than normal as long as the track was clear ahead for a suffucient distance. LZB 100 could display up to 5 km in advance.
 
 
The original installations were all hard-wired logic. However, as the 1970s progressed SEL developed the computer based LZB L72 central controllers and equipped other lines with them.

By the late 1970s, with the development of microprocessors, the 2-out-of-3 computers could be applied to on-board equipment. Siemens and SEL jointly developed the LZB 80 on-board system and equipped all locomotives and trains that travel over 160 km/h plus some heavy haul locomotives. By 1991, Germany replaced all LZB 100 equipment with LZB 80/L 72.
 
 
When Germany built its high-speed lines, beginning with the Fulda-Würzburg segment that started operation in 1987, it incorporated LZB into the lines. The lines were divided into blocks about 1.5 to 2.5 km long, but instead of having a signal for every block, there are only fixed signals at switches and stations, with approximately 7 km between them. If there was no train for the entire distance the entry signal would be green. If the first block was occupied it would be red as usual. Otherwise, if the first block was free and a LZB train approached the signal would be dark and the train would proceed on LZB indications alone.

 
 
The system has spread to other countries. The Spanish equipped their first high-speed line, operating at 300 km/h, with LZB. It opened in 1992 and connects Madrid, Cordoba, and Seville. In 1987 the Austrian railways decided to introduce LZB, and with the 23 May 1993 timetable change introduced Euro City trains running 200 km/h on a 25 km long section of the Westbahn between Linz and Wels.

 
 
Siemens continued to develop the system, introducing "Computer Inegrated Railroading", or "CIR ELKE", lineside equipment in 1999. This permitted shorter blocks and allowed speed restrictions for switches to start at the switch instead of at a block boundary.
 
Cable loops

 

The LZB control center communicates with the train using conductor cable loops. Loops can be as short as 50 meters long, as used at the entrance and exit to LZB controlled track, or as long as 12.7 km. Where the loops are longer than 100 m they are crossed every 100 m. At the crossing the signal phase angle is changed by 180° reducing electrical interference between the track and the train as well as long-distance radiation of the signal. The train detects this crossing and uses it to help determine its position. Longer loops are generally fed from the middle rather than an end.


One disadvantage of very long loops is that any break in the cable will disable LZB transmission for the entire section, up to 12.7 km. Thus, newer LZB installations, including all high-speed lines, break the cable loops into 300 m physical cables. Each cable is fed from a repeater, and all of the cables in a section will transmit the same information.
 
 
LZB route center (central controller)

The core of the LZB route center, or central controller, consists of a 2-of-3 computer system with two computers connected to the outputs and an extra for standby. Each computer has its own power supply and is in its own frame. All 3 computers receive and process inputs and interchange their outputs and important intermediate results. If one disagrees it is disabled and the standby computer takes its place.

The computers are programmed with the fixed information from the route such as speed limits, gradients, and the location of block boundaries, switches, and signals. They are linked by LAN or cables to the interlocking system from which they receive indications of switch positions, signal indications, and track circuit or axle counter occupancy. Finally, the route center's computers communicates with controlled trains via. the cable loops previously described.
 
Speed signalling

The main task of LZB is signalling to the train the speed and distance it is allowed to travel. It does this by transmitting periodic call telegrams to each train one to five times per second, depdending on the number of trains present. Four fields in the call telegram are particularly relevant:
 
Target distance
Target speed
Nominal stopping distance, known as "XG" (See below)
Distance to brake application poin

The target speed and location are used to display the target speed and distance to the driver. The train's permitted speed is calculated using the trains braking curve, which can vary by train type, and the XG location, which is the distance from the start of the 100 m zone that is used to address the train. If the train is approaching a red signal or the beginning of an occupied block the location will match the location of the signal or block boundary. The on-board equipment will calculate the permitted speed at any point so that the train, decelerating at the deceleration indicated by its braking curve, will stop by the stopping point.

A train will have a parabolic braking curve as follows:
 

where:
 
decel = deceleration
dist = distance from beginning of 100 m zone

Where a train is approaching a speed restriction the control center will transmit a packet with an XG location set to a point behind the speed restriction such that a train, decelerating based on its braking curve, will arrive at the correct speed at the start of the speed restriction. This, as well as deceleration to zero speed, is illustraded with the green line in the "Permitted and supervised speed calculation" figure.
Permitted and supervised speed calculation

 
The red line in the figure shows the "monitoring speed", which is the speed which, if exceeded, the train will automatically apply the emergency brakes. When running at constant speed this is 8.75 km/h above the permitted speed for transitend emergency braking (until speed is reduced) or 13.75 km/h above the permitted speed for continuous emergency braking. When approaching a stopping point, the monitoring speed follows a braking curve similar to the permitted speed, but with a higher deceleration, that will bring it to zero at the stopping point. When approaching a speed restriction, the monitoring speed braking curve intersects the speed restriction point at 8.75 km/h above the constant speed.

ICE full-service braking and LZB deceleration

 
Deceleration rates are more conservative with LZB than with conventional German signalling. A typical passenger train braking curve might have a "permitted speed" deceleration of 0.5 m/s2 and a "monitoring speed" deceleration of 0.71 m/s2, 42% higher than the deceleration for the permitted speed, but lower than the 0.76 m/s2 required to stop from 140 km/h in 1,000 m. The ICE3, which has a full service braking deceleration of 1.1 m/s2 below 160 km/h, dropping to 0.65 km/h by 300 km/h, has a LZB target speed deceleration of only 0.68 m/s2 to 120 km/h, 0.55 m/s2 between 120 km/h and 170 km/h, and 0.5 m/s2 at higher speeds. In between the permitted speed and monitoring speed is a warning speed, normally 5 km/h above the permitted speed. If the train exceeds that speed LZB will flash the "G" light on the train's display and sound a horn.
 
Leaving LZB

About 1700 m before the end of the LZB controlled section the central controller will send a telegram to announce the end of LZB control. The train will flash the "ENDE" light which the driver must acknowledge within 10 seconds. The display will normally give the distance and target speed at the end of the controlled section, which will depend on the signal at that point. When the train reaches the end of LZB control the "Ü" and "ENDE" lights go off and the conventional INDUSI (or PZB) system takes over automatic train protection.
 
Special operating modes

Special conditions not covered by the full LZB system or failures can put LZB into one of the special operating modes. Crossover to opposite track

As a train approaches a crossover to a normally opposite direction track the display will flash the "E/40" light. The driver confirms the indication and the permitted speed drops following the braking curve to 40 km/h. When the crossover section is reached the displays are switched off and the driver can proceed through the crossover at 40 km/h.
 
Drive by sight signal

German signalling systems have a "drive by sight" signal that consists of 3 white lights forming a triangle with one light at the top. This signal, labeled "Zs 101", is placed with a fixed line side signal and, when lighted, permits the driver to pass a fixed red or defective signal and drive by sight to the end of the interlocking no faster than 40 km/h. When approaching such a signal in LZB territory the "E/40" light will be lit until 250 m before the signal, then the "E/40" will go dark and "V40" will flash. The "V40" signal indicates the ability to drive by sight.
 
Transmission failure

If data exchange is interrupted, the trains distance measurement system fails, or the train fails to detect 4 or more cable transposition points the LZB system will go into a failure state. It will light the "Stör" indicator and then falsh "Ü". The driver must acknowledge the indications within 10 seconds. The driver must slow the train to no more than 85 km/h or lower; the exact speed depends on the backup signalling system in place.
 
Red: High-speed lines for 300 km/h (186 mph)
Orange: High-speed lines for 250 to 280 km/h (156 to 175 mph)
Blue: Upgraded lines, 200 to 230 km/h (125 to 145 mph)
Grey: Other lines, max. 160 km/h (100 mph)

 
 
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