The Christian Science Monitor has a 1 March 2006 article on the current rather sorry state of IRR, with quotes on what has happened from some names which might be familar to readers of this site.

Those trains that do operate, do so infrequently. A ticket costs just 750 Iraqi dinars (50 cents), making it the cheapest form of transport, but few are willing to brave the journey. Just three largely empty passenger trains a week make the round trip from Baghdad to the northern city of Mosul. There’s an additional passenger train that makes erratic trips between the province of Babel, just south of Baghdad, and Basra. Freight trains, the backbone of the railways, are even scarcer.

The tracks are in such poor condition that the trains travel at half speed, just 40 km/h. What should be a six-hour trip to Mosul, instead takes 10.