M3: The success story of metro replacement Part I - The butterfly effect in surface transport

In May 2023, with the handover of the last renovated stations of the M3 metro line, not only the reconstruction was completed, but also the largest bus replacement project in the history of BKK. In our interview series, we present the amazing logistical tasks that the employees of BKV, BKK, FŐMTERV, Budapest Közút and the contractor SWIETELSKY Magyarország Kft have solved - in the last 80 months

In our first interview, Robert Péter Horváth, Project Manager of the BKV Zrt. Metro Renovation Project Directorate (MFPI), Zsolt Domszky, Senior Traffic Engineering Officer of BKK and Roland Beller, Team Leader of the FŐMTERV Zrt. Traffic Engineering Office, will give you an insight into the complex process.

The renovation of the M3 metro line started more than five and a half years ago, in November 2017, with the closure of the northern section and lasted until May 2023, when the last two renovated stations were opened: the Nagyvárad tér and Lehel tér stations. Although the greatest interest was generated by the underground work, almost as much expertise, organisation and attention - and patience on the part of users - was required above ground.

During the reconstruction of the country's busiest railway line, the largest bus replacement in decades was necessary, in which the bus sector and the BKV's bus sector, as well as BKK, played a key role.

Around half a million people use the M3 metro every day. It was necessary to ensure the smooth transfer of this number of passengers to their destinations by providing replacement buses on various alternative routes and by increasing the frequency of tram services. During the metro renovation period, an average of 1 600 metro substitute buses ran daily, which means 154 drivers a day to get public transport users to one of the 20 stations on the 17 km long M3 metro line.

During the five and a half years of the reconstruction, 3 million metro trains have departed from one of the terminals and the vehicles have travelled more than 23 million kilometres. This means that if they had travelled along the equator, they would have avoided our planet 724 times.

Planning followed by day-to-day, minute-by-minute implementation

BKV Zrt. as the investor was the one who coordinated the whole project, managed it, and tendered the public procurement, not only for the metro renovation, but also for the replacement of the span.

Péter Róbert Horváth, project manager of BKV's Zrt. MFPI, recalls the early days: "The replacement had to be planned not only on the same line as the metro, but on several alternative routes to serve the passenger traffic of the given renovation phase. The reconstruction of the metro started with the planning and the work of BKV. When the first contract for the tunnel and station reconstruction was put out to tender, we had to prepare the surface infrastructure to be built. After all, as soon as the metro was shut down, the surface replacement had to start.

This had to be done in such a way that passengers could seamlessly switch to another alternative means of transport overnight to reach their destination, all in an accessible environment. Then, while the work on the respective phase was progressing underground, BKV provided assistance throughout in order to implement the above-ground replacement."

The Budapest Transport Centre Zrt. (BKK), as the transport manager of the capital, determined the number of passengers that had to be replaced in each renovation phase on the different sections. The planners developed the feasibility plan accordingly. Each site was a little bit specific. In some cases it was as simple as widening one stop, in others it was a major change to the surface transport system, affecting other traffic flows.

The original plans were to renovate the northern and southern sections together

Co-operation before the planning of the metro replacement started in 2015. The weekly meetings were attended by all the metropolitan actors that had a say in the preparation (BKV, BKK, Budapest Közút, Municipality of Budapest). The first set of plans was finalised on 28 January 2016, after which the public procurement for the construction of the surface replacement could be launched.

Planning a metro replacement during the complete overhaul of the 20-station M3 metro line was an unprecedented task. It has presented new challenges to the experts. For FŐMTERV Zrt., a team of around 25-30 people worked on the design, some of whom had experience from the construction of the M3 metro, but since then, changes in urban transport have meant that planning the replacement during the renovation has been a different task. Roland Beller, team leader of the traffic engineering office FŐMTERV Zrt., gave an insight into the project, which required a great deal of insight and a special approach.

"We have followed the planning virtually through the entire project, from the development of the construction schedule concept, through the design of what we call the 'major' replacement phases, to the development of the subway replacement route, including local traffic restrictions for the direct, above-ground work at the stations. In the first planning phase, it was established that the complete reconstruction of the M3 metro could be carried out on the basis of three "major" replacement phases, which are closely interlinked."

"The original plan was to start construction and replacement of the metro in the north and south at the same time, while in the middle (between Lehel Square and Nagyvárad Square) the metro trains would have run. However, the delay in the tender for the tunnel renovations has meant that this concept has been scrapped. Uncertain renovation tenders meant that a replacement bus route was first built on the southern section, and then, as life would have it, renovation work could start on the northern section. So, as a matter of urgency, a replacement metro route for the northern section had to be built as originally planned. The preparatory work on the southern section was not wasted, and the new route was used at the next schedule change." - Roland Beller explained the initial difficulties.

Of course, as time went on, in a year and a half or two years, the plans were overtaken by the conditions on the ground and the earlier ideas had to be rethought and updated.

Péter Róbert Horváth, BKV's Zrt. MFPI project manager, points out that the replacement schedule was also influenced by the metro's capacity. "In order to close the sections, the subways had to be reversible, and this is not possible at all stations in the metro. This effectively pre-declared that Lehel Square and Oradea Square, as a turning station, had to be operational at all times. This is in fact a limit, a framework, because as long as the station has to be operational in either the south or north direction, these stations cannot be touched."

Another factor was the number of buses available.In 2016, BKV did not have the fleet to ensure a smooth replacement with a 45-second tracking time.

"The joint reconstruction of the north and south sections was therefore impossible, as there were not enough buses available to replace them and the tunnel tender was not and has not been successful either", the project manager added.

Bus purchases and increasing the number of buses were also a major challenge

The M3 metro line is the longest and busiest underground line in the capital, which also serves as a transfer point for the M2 and the metro at Deák Ferenc tér station. During the refurbishment of each section, around 15,000 passengers had to be diverted to alternative routes during peak hours. As Péter Róbert Horváth said, only half of the passenger traffic, 8,500 people, could be transported by metro replacement buses. Therefore, alternative bus routes were planned and in some places passengers were diverted to the tram.

<Zsolt Domsky, senior traffic technology officer at BKK, admitted that they were also shocked at first by the way the task was being carried out. "When the planner outlined how many buses would be needed to carry so many passengers, we said it was impossible, as it would require practically one bus corridor on the metro line. It was clear that we could not replace it with the metro line alone, we would need alternative routes."

Yet a solution was found. "When we calculated that the minimum tracking distance was 45 seconds, which was also a theoretical peak, we almost laughed at ourselves that it was impossible."

In practice, this meant that as soon as passengers boarded the vehicles, they were on their way. Special traffic engineering, favourable traffic light tuning and bus lanes on the longest possible stretch of the route helped their smooth and uninterrupted journey.

"But eventually plans were hatched to move the remaining passengers who couldn't fit on the subway substitute to the replacement sections. That's how we launched the alternative routes. To make it clear: for example, we did not lure passengers from Havana to Határút, but took them to Népliget or downtown, and there were these very well-established new routes, as well as a single tram on Hungária körút to Lágymányosi bridge (now Rákóczi bridge). It was more sensible to take passengers around between Árpád Bridge and Népliget, so that they didn't go through the city centre. So there were many, many small options like that that had to be found" - says Zsolt Domszky, outlining the logistics.

The extremely busy schedule of the replacement buses demanded enormous discipline and a consistent pace from the bus drivers. Special emphasis was placed on making this known.

"Each bus driver has been agreed separately. We have discussed that they have a very serious task ahead of them. To keep the 45-second tracking time, they had to follow strict rules. We tried to persuade them that when the last passenger gets off, they have to step on the accelerator immediately because the lights are set and believe me, by the time they get there, they will be green"

- Domszky Zsolt Domszky described the tense pace. In the meantime, they had to ensure that the bus had time to rest, and in the meantime they had to make sure that another driver drove the bus around, because the system could not stop. They also consulted with some of the suppliers who were loading goods in front of the shops, so that they would now stop in the other small street instead of the usual place (on the route of the replacement bus). This kind of organisation, invisible to outsiders, has meant a lot of work for each of the phases.

BKV and BKK have tried to honour the bus drivers. The companies also made sure that drivers' rest periods were included in their driving times and that they were comfortable. "We made sure that there was a storage area close to the line where we could put 10-15 buses at a time, and that the drivers had an air-conditioned container where they could freshen up, have their lunch and coffee" - said Zsolt Domszky of BKK.

More improvisation than a traditional project

No one has ever had the experience to move so many buses, organise them and maintain the route smoothly - said Péter Róbert Horváth, project manager of BKV Zrt MFPI.

"The pace of construction of the stations was largely determined by the surface options. The dynamics of the system can be likened to the butterfly effect principle,which, when viewed in this way, reveals that this highly complex process was full of variables. It was a huge challenge for any company to implement."

In construction, it is accepted that there are situations when unexpectedly you have to redesign, to come up with a new solution. But during the metro replacement, there were also regular challenges for planners to solve. Roland Beller of FŐMTERV said:

"Each stage had its own beauty. In the case of the northern section, the original plan was to build a storage area behind Nyugati station in the area around Ferdinand Bridge. The owner of the land could only provide the area for a year because of a future development project, so we had to think about it. So a bus depot was planned and built in Újpest in the vicinity of Rózsa Street, which could serve the northern section of the line. Several times during the project, the original plans had to be revised and modified. Changes to the construction schedule of the stations have had an impact on the design of the surface replacement at intervals."

The biggest challenge was the surface transport project in and around the Göncz Árpád City Centre.

"I can probably say that the biggest challenge for the designers was the temporary traffic engineering works in the area around the Árpád Göncz City Centre. During the whole project, a total of 192 traffic engineering site drawings were made for this area. The site plans were used to track temporary conditions during construction, of which 100 were related to station renovations and 92 were for the construction and reconstruction of the replacement."

- Roland Beller presented the figures. The following is added by Péter Róbert Horváth:

"The Árpád Göncz City Centre was also special because a new urban district was practically built there at the same time as the metro station was renovated. Several projects were going on in parallel. One of the difficulties was that one of the contractors would have needed a working area where the replacement buses were running. In an urban environment, it is difficult to give work space where there is none."

The FŐMTERV specialist also highlights the design of the surface transport at Nyugati station. "Nyugati Square is a busy junction for car traffic, as well as for bus and tram services. Figuring out how to ensure that the replacement buses do not interfere with tram number 4 tram number 6 was a major challenge. After planning a phase, there were regularly exceptional situations that had to be resolved. Sometimes we had to come up with a new plan overnight to solve a problem."

All the companies concerned have been involved in resolving the new situations. BKK also carried out continuous monitoring throughout the whole period of the traffic congestion from a traffic safety point of view. If it was found that the traffic was not maximum accident-free, the procedure was immediately modified, but these were only fine-tuning adjustments.

A BKV and BKK expert also emphasises that there have been no fatalities or even major accidents during the five and a half years of the replacement, which proves that all factors that contributed to passenger safety have been taken into account. As they said, the feedback has also been overwhelmingly positive, with the public and the travelling public being tolerant and patient enough to accept the necessary changes.

In our next interview, we will discuss the role of SWIETELSKY Magyarország Kft., which is responsible for the traffic engineering changes required for the surface transport replacement, and Budapest Közút Zrt., which is responsible for the operation and maintenance of the capital's roads, in the metro replacement.