The OPRET, the Office for the Reordering of Transportation, headed by former Metro Minister Diandino Pena, announced yesterday that formal bidding had begun for 17 light metro trains, comprising a total of 53 cars. Bids will be received beginning tomorrow at 10 am at the offices of the OPRET. Pena said that the bids are expected to come from CAF in Madrid, Spain; Bombardier Transportation, from Canada; Alstrom Transport from France; Anslado Breda from Brazil and Rail Transportation Division of Siemens. The bids need to come accompanied with their source of financing.