Line 4 is under negotiation with China North Industries Corporation (Norinco)for $680 million, but the company is understood to be seeking more money to reflect increased equipment prices. On line 3, the local Rail Transportation Industry Company (Rtico)has still not brought a foreign partner to the table as required. The client, Tehran Urban & Suburban Railway Company (TUSRC), says it hopes to resolve outstanding issues with its preferred partners on the project and avoid a retender.

The two companies were chosen as the best placed bidders for the projects after a long-drawn out tender process that ended in 2004. However, negotiations have continued since then, with Rtico, a subsidiary of Industrial Development & Renovation Organisation (IDRO), seeking a partnership with Germany's Siemensor Canada's Bombardier. Both companies were unsuccessful bidders in the original tender. TUSRC says it will request local companies to lead the bidding groups on lines 6 and 7 and bring foreign equipment suppliers and finance with them.