Sydney's rail network is under extreme pressure. Credit:Ryan Stuart The chaos last week – even before patronage returns to normal levels when most people return from summer holidays – came just six weeks after the introduction of a new timetable. It has boosted train services by 1500 a week but crimped the network's ability to recover from delays caused by major incidents. And now, with the rail union threatening the first strike in almost two decades, Sydney's train network is under acute stress. Yet buried in more than 600 pages of government documents obtained by the Herald under freedom of information laws are high-level concerns about another threat. About 200 fires occur each year on trains and at stations across Sydney's rail network. While most are minor, a Transport for NSW report marked "Cabinet in confidence" in January 2016 warned that "where fires occur in the underground network, the consequences have the potential to be catastrophic". Analysis by Arup, a global firm of consulting engineers hired by the transport agency, ranked Town Hall most at risk from fire within Sydney's underground rail system of 20 stations, six covered stations and 60 tunnel sections.

Peak hour begins at Town Hall station. Credit:Ryan Stuart Transport for NSW's Fire and Life Safety report reveals one of the reasons Town Hall easily ranked highest – well above other stations with the exception of Redfern – was because of connections to shopping malls, such as the Queen Victoria Building "with in some cases no fire separation, which increases the likelihood of a fire". "Other key factors at Town Hall station included unprotected structural steel frames [columns and beams] at platform level; the concourse is directly above the platforms and all areas are open and connected," the report said. The meltdown on the network last week caused major overcrowding at Town Hall. Credit:Louie Douvis "There are no smoke exhaust or ventilation systems. The station also has a high level of patronage and high number of trains per hour with multiple lines running through station."

During their analysis in 2015, risk assessors from Arup interviewed staff at Town Hall about how they dealt with fire training and incidents. In one interview, a duty manager told an assessor that "it's probably at least three years since the staff trained in first attack fire-fighting equipment". The sole escalators to the Eastern Suburbs Line at Redfern Station. Credit:Dominic Lorrimer Where fires occur in the underground network, the consequences have the potential to be catastrophic. Internal Transport for NSW report "Evacuation training does occur, but not at Town Hall station. It occurs elsewhere, because Town Hall doesn't close," the manager said. The Transport for NSW report in 2016 did note "a very significant" amount of work in the past, and underway at the time, to mitigate fire and life safety risks. That included a review of staff training, improved "separation of back of house areas" and an investigation of "future proofing smoke exhaust at Town Hall during current upgrade".

The silver S-sets and other older trains in the fleet pose "greater risks" in an evacuation. Credit:Michel A Bunn About the time of that report, a revamp of Town Hall station began that included an "upgraded fire detection, sprinkler and alarm system, installation of a smoke exhaust system throughout the concourse and enhancement of emergency lighting and exit signage". Yet almost a year later, concerns were still being raised at the highest levels within Sydney Trains. Station staff at Town Hall temporarily stop commuters from entering the platforms last week to avoid dangerous overcrowding. Credit:Louie Douvis A briefing note from Sydney Trains chief executive Howard Collins in November 2016 warned that "fire and life safety concerns have been raised for a number of years, and need to to addressed before an incident occurs".

Most of the briefing note to Transport for NSW's deputy secretary of freight strategy and planning, Clare Gardiner-Barnes, has been redacted. However, it shows that Collins recommended that the lead transport agency conduct a "future requirements study of Town Hall station". One of its tasks would be to again "confirm the extent of the fire and safety risks". Sydney's rail network is under extreme pressure. Credit:Dominic Lorrimer Collins, a Londoner who has been Sydney Trains CEO since 2013, was working for London Underground at the time of the Kings Cross fire in 1987 that claimed 31 lives. Transport for NSW and Sydney Trains did not answer questions about the outcome of that "future requirements" report, if indeed, it has been carried out. The documents also reveal that the City of Sydney Council privately raised concerns about fire safety at Town Hall station in 2016, six months before the briefing note from Collins' was sent to the bureaucracy's hierarchy.

The City of Sydney said this week that "we sincerely hope that Transport for NSW is doing everything within its power to ensure the safety of all passengers". "Given Town Hall's recent experience of over crowding, it is important that fire and life safety is managed exceptionally well," it said. In response to questions, Sydney Trains said in a statement that it had been "proactively improving fire safety at Town Hall" since 2016, which included upgraded fire detection and alarm systems, and the installation of a smoke exhaust system in the concourse. "We also have an ongoing program to reduce the risk of fire in tunnels, such as upgrading tunnel cables using fire-resistant cables," a spokesman said. "The safety of our customers and staff is always our highest priority." Like other stations in the CBD, Town Hall is under pressure from rapidly increasing demand. Already, more than 1 million people travel on the city's rail network every week day. And the government is forecasting patronage to surge by 21 per cent on weekdays – and by up to 120 per cent on weekends – over the next three years. Many of those extra passengers will travel on trains in and out of the City Circle line, and to stations such as Town Hall.

It means the management of crowding at train stations, especially Town Hall on weekdays, is becoming more of a priority. Town Hall was at the centre of the chaos during the timetable meltdown last week, and on December 11. Dangerous levels of crowding forced staff to temporarily stop passengers from entering platforms and, during the first meltdown in December, urge people to avoid Town Hall and walk to Central Station. While a $20 billion metro train line to be built under the CBD is designed to reduce pressure on Town Hall, it will not be opened to passengers for another six years. South of the CBD, Redfern Station is also under growing strain, particularly when thousands of Sydney University students and staff pass through it on their way to the nearby campus at Camperdown. Apart from minor improvements such as a installing a lift, the station has had little in the way of an upgrade for years. Two platforms for the Eastern Suburbs Line at Redfern, which are deep below the ground, were ranked the second most vulnerable to fire on the rail network in the Transport for NSW report in 2016.

They have "greater risks" than at the other stations on the Eastern Suburbs line, or any of the tunnels, because it "has only one set of escalators to exit from the platform". "This means all of the occupants have to exit through a single point. The stairs and escalator have open voids so that smoke can continue up into the mezzanine level," the report said. "Also there are unprotected steel beams over the tracks and large storage areas with unprotected steel at mezzanine level, highly dependent on sprinklers and compartmentation." Two years on, Transport for NSW said in a statement that it was "investigating options" to upgrade the station, which would include improved customer safety.. The internal reports, and others leaked in recent weeks, point to a rail network under extreme pressure.

In order to meet surging demand, the government put on 1500 extra weekly services as part of the new rail timetable rolled out on November 26. That has meant Sydney Trains has had to press its S-set trains dating to the 1970s into service more often. Commuters often refer to them as "sweat sets" because they are not airconditioned, making for uncomfortable trips on summer days when they are packed during peak periods. Sydney Trains chief executive Howard Collins has conceded that they are "not acceptable", and he wants them gone by next summer. Transport Minister Andrew Constance expressed his own reservations this week about the S-sets. "I didn't want to bring the S-sets back onto the network but I had no choice because people are getting to the point where they can't get onto trains," he said. But aside from passenger comfort, Transport for NSW's 2016 report reveals the silver S-sets and other older trains in the fleet pose greater risks in the event of a fire evacuation. That is because they have "poorer fire retardancy levels, higher fire loads, poorer detection systems, slower detrainment facilities and no internal CCTV". "This means that detection and evacuation can be slower while smoke levels are increasing, creating a potentially catastrophic scenario [albeit with a low expected frequency]," the report said.

"The older rolling stock such as the S, K, C, and V sets and Tangaras, do not have internal CCTV or smoke detectors. While Tangaras and V sets have passenger emergency alarms, the S, C and K sets do not which can significantly delay the notification of train crew of a fire on a train." The vast majority of risk, even for stations, comes from train fires, according to a risk report in late 2015 by Arup for Transport for NSW. "Therefore, reducing the frequency and/or scale of train fires could help mitigate fire risks across the underground network," the report said. "It is considered that this could be done largely through improvements to rolling stock." Arup also advised that running trains on lines "at shorter headways or more closed spaced ... can increase the life safety risk". Just over half the state's fleet of electric trains is more than 20 years old, and 28 per cent more than three decades, according to the most recent government figures.

The first of 24 replacement trains for the S-sets are due to begin service in June, but forecasts two years ago were for the C and K sets to remain until 2024. In its response to questions, Sydney Trains said the older trains in its fleet had a "built-in system designed to resist any fire" and, when refurbishments and repairs were performed, "modern fire-resistant materials are used to further reduce the risk of fire". Behind the scenes, improving safety on the rail network has been the subject of debate within the transport bureaucracy for years. A topic has been the need for a ventilation system for Sydney's underground rail tunnels, the cost of which has been estimated to range from several hundred million dollars to $1 billion. In 2013, an adviser on fire safety, Arnold Dix, reversed his recommendation years earlier that the government should not install an emergency ventilation system. "All modern railways, full stop, have got ventilation systems that allow you to control the flow of air if something was to go wrong," he told the Herald in 2013. "Sydney doesn't ... and it should." In contrast to Sydney, Melbourne's underground train loop has a ventilation system, which can be used in fire mode – effectively a purge system – as an enhanced safety measure.

The daily headlines of the last week about an imminent strike by rail workers overshadow bigger concerns about safety and how the network will cope with the increase in new services from the new timetable and surging patronage. The strain on the rail system will escalate when two of its existing lines are taken out of service for long periods in the coming years to allow them to be converted to carry single-deck trains as part of the government's $20 billion metro rail project. The metro line will be run separately to the existing train network. The first stage between Rouse Hill in Sydney's north west and Chatswood will be operated by Hong Kong rail operator and property developer MTR, which is also considered likely to win the contract to run the second stage of the line onto the CBD and Bankstown in the west. In a highly critical assessment of the metro project obtained by the Herald last month, four of NSW's top former rail executives warned that the metro train plans will result in "degradation of the robustness and reliability" of the existing rail network. Their fear is that it will "ultimately lead to the total network becoming gridlocked and unworkable". And they warned the "takeover" of the existing rail line between Sydenham and Bankstown for the metro train project will remove a "relief valve for the network".

"Any new system needs to add value by adding to existing capacity, not by taking away part of the existing network in the name of progress," they said. Even when the second stage of the metro line is opened in 2026, the existing rail network will be relied upon to carry the vast bulk of passengers across Sydney. "The real problem is that the current network needs expansion whether you like it or not," another veteran of Sydney's rail network says. "The Bankstown Line conversion will not enhance the existing network. As soon as they close Epping to Chatswood it will get worse, and if they continue and close down the Bankstown Line it gets significantly worse again." The events of the past two weeks represent the perfect storm for the government and those running Sydney's rail network. Yet it is just the start of the challenges ahead for the backbone of Sydney's transport, and a crucial cog in its economy.