My experience with Singapore MRT (both SMRT and SBS Transit lines) are 5 minutes peak, 7 minutes non-peak. Most US and Canadian lines run at 3 minutes peak and 5 minutes non-peak. Tokyo and HK lines are fastest, 2 minutes peak, 4 minutes off-peak.
singapore is 5 mins for peak ? thats too long !!!!! . MRT dont want to buy more trains ? save money for their CEO pockets ? . HK also have double-track commuter ? i dont know about HK train system .