 Complete the following phrase:  Trenes de Buenos Aires, a company formed in 1995 to take over rail concessions granted by the Argentine government, as part of railway privatisation during the presidency of Carlos Menem, operated commuter rail services over Sarmiento and Mitre lines in Buenos Aires which had previously been run by state-owned companies since nationalisation of the railways in 1948. In spite of the large state subsidies received by the company a serious decline in the standard of its services, and fatal accidents especially, the 