explanation.txt

BUS (its easy)..

when driver logs in he enters the route
when user searches route, send the query to db and return an array of bus objects that have the same route
then extract the location information in the front end and place marker

TRAIN (its harder..but not really)..

when driver logs in they enter the START and END location 
this is sent to the google API called Directions Service with a appropriate request query object(like Trains only etc)
the data is returned and we take the route locations (Directions Route Legs) and place the name/id of the station in our train object.stops
send the train object to database(not realtime)
when user searches for train (start to stop) we send this as a query to the db to return array of trains who have (start to stop) inluded in their object.stops
then extract the location information in the front end and place marker