i want to insert sound in my model locomotive ..

so can u tell me plz which things i required.?

supply voltage 12v DC

 

http://www.modelrec.com/train-controls/sound-systems.asp

should give you some idea of the options.

 

You may want to PM this member. He's a model railroader.
http://forum.allaboutcircuits.com/member.php?u=107359

 

Hello,

Perhaps the circuits on these pages might interest you:
http://members.shaw.ca/roma/train.html
http://members.shaw.ca/roma/train_horn.html

Bertus