Train Ticket

Woodlands station has two areas, one deals with Malaysian immigration and the other with Singapore immigration. The train is very, very slow due to construction works on the line. It can take more than 6 hours. You get off the train in Woodlands and go through Singapore immigration. The train line no longer runs to Keppel Quay. To get a train back to Malaysia, you go to the station concourse and go through Malaysian immigration before you can board the train.  I think you may have some issues by trying to just do a turn-around at Woodlands.

i need 24hr to return back malaysia agan . . i dnt hav problm if run late also

Immigration are very strict these days and often interview people to find out why they are returning. Indian passport holders are one of the nationalities are likely to be stopped and questioned. So legitimate reasons for going to Singapore and returning to Malaysia will be needed. I think you will have to buy a return ticket to get into Singapore (which is difficult from Malaysia but you can try at Sentral Station to do this where you get your ticket in advance and also make a seat booking).  You will also need proof that you have resources to support yourself in both countries.

am not staying in singapore . . . same day return back to Malaysia again

Just saying you may run into problems by doing that.

Remember the immigration people can stamp your passport and only give you a very short time to remain in Malaysia (e.g. 1 or 2 weeks perhaps)

You can also do the journey by coach.

y 1 or 2 week i have visa for 30days na stay at hotel r room . . i travl by train with onward retun tickte

Immigration officials can decide how long you can stay in Malaysia - they enter a date into your passport and nothing can change that.  Your visa is for a maximum of 30 days. It has happened to me and many other people.