LLULL Sastre, a construction company, is to begin work today on the banks of the railway line between Inca and Manacor, the scene of a derailment accident last Saturday in which 13 people were injured. Sources at the regional ministry of Public Works and Transport, headed up by Mabel Cabrer, indicated that works will be carried out with maximum thoroughness. Such emphasis, claimed the minister, is in contrast to the haste with which the retaining walls of the banks were originally rushed to completion to comply with the previous Socialist government's inauguration schedule. In essence, the works will consist of taking down the temporary retaining walls to be replaced with permanent structures and lined with dry stone. Through accentuating the solidity and permanency of the refurbishment work, Cabrer believes she can guarantee that the work under way will be a final solution to complying with all the standards of security and quality that passengers require and to fulfill the promise of the current Balearic government to provide the best possible railway service for the Island's inhabitants. The ministry of Public Works, which expects to open the railway line as quickly as possible, was clear on the issue that although work is being carried out to get the service up and running again, exhaustive investigations are still ongoing to determine the exact circumstances surrounding last week's derailment. The accident was caused by a railway bank collapsing onto the track near Petra.