How to ouput in single row in sql server

Question

select mainline+'/'+subline from table1 where mainline='54326'

Here I m getting output like  this

o/p:

Mainline    

54326/1

54326/2

the above query i m getting output in two line

but i need an single line output like i mentioned below

Mainline

54326/1, 54326/2

anybody please post solution for this.....