They are bringing new rakes.But the main problem is, Metro Railways,Kolkata is under IR. Indian Railways, better to say Rail board is only interested to buy rakes mostly from ICF (Yes,Kol Metro is also buying rakes from CRRC). ICF on other hand produces rakes which have numerous faults, again the reason may be they lack testing track. So it can be concluded that Metro Railways, being under Indian Railways, is forced to take rakes from ICF,though they are faulty. While other metros being private,buy good rakes from other companies.