THE construction of Barcelona’s first automatic metro line has not gone entirely to plan due to funding constraints. Nevertheless, the project to build a 47.8km north-south line skirting the western side of the city has pioneered several innovative design features, while Barcelona Metropolitan Transport (TMB) took the opportunity to change the way not only the new automatic line but also the entire metro network is operated and maintained.
The new line, which is operated as lines 9 and 10, will eventually run from Can Zam and Borg in the north to the airport and Zona Franca in the south, sharing a common section between Bon Pastor and Can Tries-Gormal. The line will eventually have 52 stations of which 17 will provide an interchange with other lines, and will serve several important traffic generators such as the airport and port logistics area, the main court of justice, the new high-speed station under construction at La Sagrera, the university, Barcelona Fira exhibition centre, Sant Pau Hospital, and FC Barcelona football stadium at Camp Nou.
Completed in stages in December 2009 and 2010, the two northern branches run from Can Zam (Line 9) and Borg (Line 10) to Bon Pastor where they merge and continue as one line to La Sagrera totalling 11km and serving 12 stations. The 19.6km southern section with another 15 stations from the university to the airport (Line 9) opened in February 2016. The 5.9km Line 10 branch from Can Tries-Gormal to Zona Franca has also been completed, enabling trains to reach the depot, although this section is not open to the public yet.
Some of the tunnelling for the remaining 11km central section has been completed leaving about 5km remaining. TMB is considering ways to build the final underground section as cheaply as possible, which might mean delaying the construction of some stations until funds become available. The Catalan government applied for a €740m loan from the European Investment Bank in May to help fund the completion of the project, but the application is still being appraised.
“We need to complete the line because we expect up to 20% more traffic in the future, as people switch from driving diesel cars and try to use their cars less,” says Mr Vicenç Rius Morena, TMB’s automated metro project manager. “Traffic is already growing at 5% per annum.”
Building lines 9 and 10 has involved three distinct methods of construction. The southern sections pass through a river delta area at sea level where it was possible to use conventional techniques comprising a 9m-diameter double-track tunnel with 11 stations on the airport branch accounting for 22% of total construction, and a double-track viaduct with four stations on the southern portion of the Zona Franca branch accounting for another 8%.
However, the remaining 70% of the line passes through a hilly part of Barcelona which is also densely populated so TMB chose an unusual method of construction consisting of a 12m-diameter tunnel with one track above the other. The upper and lower tracks in the tunnel are connected at intervals by ramps. The space beside each track on the upper and lower levels acts as a safety zone for use in an emergency.
The 36 so-called shaft stations are up to 80m below street level which meant that connecting the station entrances to the platforms by escalators would be impractical, so banks of high-capacity lifts are provided instead. The lifts are incorporated within a single shaft while the platforms are built within the tunnel. This design means that station construction works on the surface occupy less space and therefore cause less disruption than with conventional methods, while there is no need to construct station boxes underground in which to build the platforms, resulting in lower overall construction costs. This technique also means that it will be possible to build some stations on the missing central section after it opens without disrupting train operation.
“We can prioritise the operation of the station lifts so that they are at the bottom of the shaft when a train arrives or at the top when there is high demand from passengers entering stations,” says Rius. “Station automation is a key objective for us.”
Lines 9 and 10 are equipped with a Siemens communications-based train control (CBTC) system rated at GoA4, the highest level of metro automation. As a result stations are fitted with platform screen doors, which Rius says have proved extremely popular with passengers with a 90% approval rating.
Trains and stations are controlled from a main control centre (PCC) and an emergency centre (PCE), which are synchronised. There is also physical and logic integration of subsystems.
“We are just two clicks away from changing the service,” Rius says. “We had to work hard with the signalling, passenger information and rolling stock suppliers to get the right passenger information system so that we can keep passengers informed if we change the service frequency or operation.
“We prefer to say this is a totally-attended service because we have live streams of information flowing to the OCC and we can remotely diagnose and react to what is happening on the trains. We can change some of the systems on the trains and reset the passenger emergency button remotely.” The system also allows TMB to remotely activate stations at the start of service and shut them down at the end of the day.
The completion of the first sections of lines 9 and 10 mean that already 25% of the Barcelona metro is now fully automated. This prompted TMB to rethink the way it operates the entire metro.
“You can buy the best technology and infrastructure, but you cannot buy the best operating model,” says Mr Ramon Malla Castells, TMB’s director of strategic projects for the metro network. “So we had to think how we could push the whole network towards a new operating model.”
Prior to the change, TMB had drivers, station masters and ticket sellers, station managers and operating managers. These roles have now been replaced with customer care agents and operating managers for the conventional lines, and a single role of operating technician on the automated lines 9 and 10.
Malla was quick to point out that staff and trade unions were fully consulted about TMB’s plans to introduce the new operating model.
“We don’t have train drivers anymore, as all operating staff can drive trains so we rotate their duties,” Malla says. “Operating an automated line is boring because nothing happens. We also needed a revolution in maintenance as well - the traditional borders between roles have changed.” Operating technicians are freed from repetitive routine tasks as they switch between patrolling stations and trains, to working in the control centre or maintenance depot. “Our staff feel they are the owners of the service because they are dealing with customers and the system,” says Rius. “They feel more empowered and operating staff are peers as there is no hierarchy.” TMB also operates a bonus system to improve performance and has seen a reduction in absenteeism since this was introduced.
One of the keys to success is knowing the location of not only the trains but the staff as well. “We now have roving staff with a response time of less than 12 minutes and an average of 8 minutes,” Rius says. “The location of each person is monitored from the OCC so that the person closest to an incident can be identified quickly. We have some staff permanently located at the very busy stations or at peak times. The focus is to ensure operating continuity so that there is no disruption.”
The tetra radio system is critical because TMB is not allowed to operate an automatic train if it cannot communicate with passengers. “There are a lot of critical interfaces between subsystems such as the platform screen doors and the passenger information systems so we have a chief of automated lines to monitor them,” Rius says. “There is also one person in charge of fixed installations.”
TMB has suffered a couple of major failures since it opened the first section of Line 9. One was caused by a signalling failure and the other by a communications breakdown. “With traditional signalling we have people who know how everything works and how to fix any problem, but with computerised systems everything is inside a black box and we are dependent on our suppliers to solve major problems,” Rius observes.
Nevertheless Rius says the new operating and maintenance model has been a “game changer” for TMB, and the trend is clearly towards more automation. “Currently 23% of cities in the world with a metro have at least one automatic line,” Rius points out. “We expect a 10-fold growth in automatic metros in the next 10 years.”