Background
Pioltello is a municipality of 37226 people (as of 2019) in the north of Italy, located in the Lombardy region 8km/5mi east of Milan and 37km/23mi southwest of Bergamo (both measurements in linear distance).
Pioltello lies on the Milan-Venice Railway, a 267km/166 mi double-tracked electrified main line opened between 1842 and 1857, at the time on a longer routing (which was shortened to today’s route in 1878. Today the line sees mostly passenger services, from regional trains to international express services with a few freight trains in between. Two weeks before the accident a maintenance train had scanned the tracks in the area, finding advanced wear on a piece of track 2km/1.25mi east of the site of the accident. The operating company, Trenord, noted the degree of wear to be observed and that the section of track would likely soon need replacing. Tests like that are conducted every two weeks, meant to spot wear and other damage to the tracks.
The train involved
R 10452 was a regional passenger service provided by Trenord from Cremona to Milan carrying a total of 350 people including the crew. Pushing the train from the rear was Trenord series E.464 number 458. The series E.464 is a four-axle electric passenger locomotive made by Bombardier (formerly ADtranz) since 1999 for service with various Italian rail service providers. The locomotives measure 15.93m/51.7ft in length at a weight of 72 metric tons and can reach a top speed of 160kph/99mph thanks to a power output of 3500kW/4700hp.
Bombardier considers the locomotives part of their TRAXX-family, with the unique feature of having two significantly different ends. The leading end features a standard cab with a slightly streamlined design while the rear features a luggage compartment with a vertical end wall and a gangway connection matching Italian passenger cars. The “blunt” end only features a reduced control desk for shunting operations as the locomotives only ever run in connections with push-pull trains that have a full control cab in the end car.
On the day of the accident the train consisted of five type MDVC four-axle passenger cars, including a control car (called “Semipilota”) at the far end. The type was made between 1980 and 1990, with over 1400 cars being made.The standard cars measure 26.4m/86.6ft in length at a weight of 39 metric tons and can either seat 82 people (all second class) or have a split configuration with 44 second class seats and 28 first class seats.
Leading the train at the time of the accident was an MDVC control car, as usual for these trains. Control cars feature less seats than standard passenger cars and instead contain a more or less aerodynamic cab on one end with full drive controls (essentially duplicating the locomotive) along with a full set of lights. While they reduce passenger capacity these cars allow the locomotive to be remote-controlled, skipping the need to move the locomotive to the other end of the train when it turns around. Trenord (as far as I could find out) uses two different styles of control car on these trains, but the specs are the same. The control cars are the same length as the regular cars and weigh the same, but only feature 60 second class seats. Like their regular counterparts they are permitted to travel at 160kph/99mph in the TE-version (with electric locomotives), while the diesel-version only goes 130kph/81mph. By 2009 more than half the cars (including regular ones and control cars) were subjected to a refurbishment-program, upgrading the interiors and giving the cars a new paint job preparing them for several more years of service.
The accident
In the early morning hours of the 25th of February express train R 10452 is approaching Pioltello station at approximately 140kph/87mph on its way to Milan. Suddenly, a short distance east of Pioltello station, the leading axle of the third car leaves the tracks, pulling the following car with it while the couplers and leading cars keep it largely aligned. Passing through the station CCTV-cameras capture the train cars slightly out of alignment, with smoke and sparks emitting from the derailed wheels as they’re ground along the rails. The driver of the train notices that something is off and triggers an emergency stop, but it’s already too late to avoid the impending disaster.
Leaving the station (where the edge of the platform helped to hold it back) the third car slowly moves to the left, increasingly breaching the rail line’s structural clearance. At 6:57am, moments after the derailment started and still travelling at full speed the leading wall of car 3 strikes and mows down two support poles for the overhead catenary, ripping it off the leading two cars. The second impact spins it around, leading it to hit a third pole with its side at almost 90° to the tracks. In an instant the heavy train car is folded in the middle by approximately 40°, destroying crucial survival space, while the rest of the train derails and comes to a stop behind and next to it. Two kilometers lie between the site of the derailment and the site of the wreckage, a distance the train covered in just 51 seconds. Three people die in the derailment, with 110 being injured (10 of which severely).
Aftermath
Minutes after the accident the first responders reached the site of the accident, within a short time 473 responders along with 28 ambulances and 2 helicopters got involved in the rescue effort. The driver and passengers in the leading two cars were largely unharmed, while the third and fourth car held most of the injured survivors along with the victims. The forces of the accident had caused severe damage to cars 3 and 4, requiring responders to cut and bend metal out of the way to rescue passengers and recover the bodies. By the time the train car had essentially T-boned itself on the third catenary support pole in its path it had lost so much speed that the concrete foundation of the pole withstood the impact of the 39 metric ton projectile, folding the body of the train car around itself like a huge coke-can.
Initially a technical defect on the train is suspected, aided by a whole wheelset (bogie) being found at the rear of the wreckage where the locomotive came to a stop. Could the whole wheelset along with its two axles have somehow separated from the train? However, there’s no evidence of anything lifting the train car high enough for the bogie to actually separate, and while it is damaged it is largely in one piece. Furthermore, none of the passengers recall a lifting-motion, while several from cars 3 and 4 report a sudden strong vibration seconds before the accident. Following damage to the tracks to the east investigators end up at the worn section of track flagged by the maintenance crew two weeks prior. There are no longer just cracks in the steel, a whole 23cm/9in of the upper section of a rail are missing.
Investigators piece together that each passing wheel had advanced fatigue-cracks in the rail, aided by its location at the end of a bolted section giving it a slight degree of up and down flexibility. When R 10452 passed over the damaged spot the cracks completed, breaking a piece out of the rail. This took away lateral support for the trains passing over the spot, and the leading axle on car 3 just happened to slightly move to the damaged site as it reached the damaged spot. In a second the affected wheel’s flange left the rail, aided by the two sections of rail having slight movement against each other (not present had the piece broken off the middle of a rail rather than the end).
At this point, the train was by all means doomed. There was no way for the driver to know what was about to happen, and even if there was there was not enough space to stop. Trains always slightly move left and right, with flanges on the inside of each wheel limiting that movement by rubbing up against the rail. The gap in the head of the rail was just large enough to take away just enough of that support just as the train car moved towards that side. It is arguable that the accident could’ve been worse had the derailment happened a few hundred meters further east, which might’ve led to the derailing train to crash onto the platforms at Pioltello station where there were more obstacles and also people waiting for trains not expecting a 39 metric ton lump of steel to come flying towards them at 140kph/87mph. With the lack of daylight at the time of the accident they might not even have seen it coming, literally.
When it came to light that the damaged section of track had been scheduled for replacement “in the near future” rather than replacing it more urgently this raised criticism towards the Italian railway’s handling of their regional lines. In the years preceding the accident Italy’s regional railways had suffered several budget-cuts, which were blamed for the lacking urgency of the track-replacement that could’ve prevented the accident. It was largely agreed that, if there would’ve been more funding available the “needs replacing now”-threshold could’ve been lower, allowing the damaged section to be replaced earlier. The site of the accident is one of Italy’s busiest sections of railway infrastructure, seeing over ten thousand passengers per day, and it was widely seen as unacceptable that “advanced damage” in such a critical point still took over two weeks to be fixed while the track was in full service.
Pepe Sala, at the time mayor of Milan, chewed out the infrastructure ministry’s focus on giant “halo projects” like a bridge over the Strait of Messina separating Sicily from the Italian mainland. He pointed out how high speed lines had seemingly endless budgeting and attention while regional lines mostly used by commuters, like the one at Pioltello, faded into the background, getting reduced priority and budgets. He said that there can’t be a separation between high speed and regular lines, and that the whole railway network has to be treated equally to get a solid infrastructure. Fatally, the line the accident happened on was especially known for too few trains, which were then often overcrowded and, at an average age of 17 years, on the older side of Italian railways, just giving further example of the difference in attention and budgeting.
A few months after the accident the local public prosecutor’s office started legal proceedings against a manager and the operational director of Trenord and the manager and general director of RFI (the company in charge of maintaining the infrastructure) on charges of negligent endangerment of rail traffic. As of writing this article (October 2021) the proceedings appear to be ongoing.
In 2019 a small memorial was constructed in the nearby town of Caravaggio, consisting of an engraved steel plate with three birds (presumably one for each victim) stylized along the upper edge standing in a flowerbed.
The refurbished MDVC-cars remain in full service with no end-date known at this point, while those not selected for refurbishment are being retired and presumably stripped and scrapped. Of the 728 series E.464 locomotives all but one are still in service, with only unit 029 having been scrapped after suffering severe damage in a 2009 accident at Milan main station. Similarly to the MDVC-cars there is no end of service in sight, with a few locomotives just recently being moved into long-distance services, sometimes running with a locomotive on either end of the train to make up for the lack of a control car on some intercity express trains.
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