Bangladesh today signed a loan dealwith a Japanese development agency for construction of the country's first-ever metro rail system. The system is estimated to cost 2.8 billion US dollars and is intended to ease Dhaka's traffic jams.Traffic in Bangladesh capital, home to 15 million people, is among the slowest in the world with commuters spending three-to-four hours in jams daily. A mix of 200,000 motor vehicles and another half-million cycle-rickshaws clog the roads.Officials said, the proposed 20.1-kilometre ground and elevated railway will stretch across Dhaka from north to southwith 16 stations and will ferry four million commuters every day, easing the jams substantially.The metro-rail construction will start in 2016 and end in 2021.