Bari - Italian officials on Wednesday pointed to delayed, EU-financed rail improvements and the "risky", antiquated telephone alert system used in parts of Italy as possible underlying causes of a violent head-on train crash that killed dozens of people.Recovery operations continued on Wednesday using a giant crane and an extra locomotive to remove the mangled cars and debris of the two commuter trains that slammed into one another in the neat olive groves of southern Puglia on Tuesday.Critical conditionThe official death toll stood at 23, including a farmer working his fields who was killed by flying debris from the crash. The prefect of Barletta, Clara Minerva, said relatives reported another four people unaccounted for and suggested that their remains could have been scattered within the wreckage, particularly in the area of highest impact."Some remains have been recovered and on these DNA and other tests are underway," Minerva said.As a result Transport Minister Graziano Delrio put the provisional death toll at 27. Local officials said that of the 51 people originally hospitalised, 27 have been released. Seven of those still hospitalised are in critical condition.Delrio confirmed that the particular stretch of track between the towns of Andria and Corato didn't have an automatic alert system that would engage if two trains were close by and on the same track. Rather, the system relied on stationmasters phoning one another to advise of a departing train.The phone system "leaves an entirely human management and is among the least evolved and most risky ways of regulating railway circulation," Delrio told parliament. Under the system, he said, the stationmaster can only allow the train to leave if it is confirmed that the line is free at the arrival station, allowing only one train at a time on the single railway.He said the single rail track used in the area isn't dangerous if "advanced technology is applied."Second trackAndria Mayor Nicola Giorgino said the crash was particularly tragic and "paradoxical" since work was to begin within a few months to build a second track on the route.In fact, the work was supposed to have begun years ago and EU funding was secured when it was first proposed for the 2007-2013 period. According to the national investment and development agency Invitalia, the EU Regional Development Fund had approved 62% of the €180m investment into the north-Bari rail improvement that included a second track for the Corato-Andria line.But it was never built. Delrio didn't explain why, but noted that Puglia officials had secured funding for the 2014-2020 budget and that bidding for contracts was to have begun July 19.Trani Prosecutor Francesco Giannella said the delay in the track-doubling work would be part of the investigation. "We will investigate the delays of the work on the line and on the deficiencies in the security system," the ANSA news agency quoted Giannella as saying.