Indore is well connected by trains from almost all the big city’s. However frequency of trains may be one or two trains a day.
So those coming from south can get down at Khandwa and can take bus for Indore. It’s 135 km and a 3.5 hours journey. Khandwa Bus Stand is outside the Railway Station and five minutes walk from there. AITSL (Indore City Bus) also operates from Khandwa. More details at http://www.citybusindore.com/index.php?page=sky-bus. For booking one can use http://www.nafeestravels.com/
Other nearby station is Bhopal which is a railway junction. Train coming from south and heading towards Bhopal may pass through Khandwa. From Bhopal, Volvo buses are available for Indore (http://charteredbus.in/AvailableRoutes.aspx). The Chartered’s office is just outside the station and they have a pick-up service from there as their bus stop is at some place else. Bhopal is around 180 kms from Indore and its around 4/5 hours journey.
Many trains are connected to Ujjain which is around 60 kms from Indore. The bus journey to Indore from there takes around 1.5 hours.
Those coming from North can also get down at Ratlam or Ngada and can take bus or train (Ratlam is around 135 kms away from Indore and is approx. 3.5 hours journey)
From Indore Railway station or Bus stand
Details coming soon. Ubar and Ola have services in Indore so one can also avail those services.