This is not the suburb railway I am talking about. The Metro style suburb railways are Paris RER, Beilin S Bhan or Tokyo Yamanote Line (山手线) with frequency of at least every 5-15 minutes or less.
Beijing -zhangjiaokou railway line is just a regular main railway line has less than 10 suburb trains a day. Not the concept of suburb railway for mass transport.
You are very rude. I am trying to discuss with you but apparently you need more knowledge.
Beijing will have the first real suburb railway line : northeast railway. It uses the existing northeast ring railway and add 2nd track and more stations. It will be operated as Metro fashion with very high frequency and integrated ticking system with Beijing Metro.
en.wikipedia.org