I have uploaded the dual horn wap-4 loco file to the train-sim.com. Just type "indian horn" and there you get it.See file id.zip for installation procedures ....
Thnakyou!!!!!!!

HELLO DINESH
SORRY for this too late a reply as i was really busy with a lot of in and out sorta work,now that i'm back and the wap4 model is ready for its debut here and i will be releasing it along with the wap4 dual horns you had provided me long back.
thanks