yes, i like tielu.org (originally referred to ft by rkkwon). it is really comprehensive easy enough for even novice chinese speakers to navigate (select your province first and your city second)

however, with respect to the OP, i don't think shanghai-suzhou warrants a whole lot of research. in fact, i usually just take busses on that route because the train station is too much hassel for such a short trip (in spite of the high frequency, i've spent hours waiting there because trains were sold out). the return trip is a bit more managable.