The Engineer's guild is a great aid to the dwarven army, as they give them Warmachines, gunpoweder weapons and occasionaly an engineer. Engineers are tough men from their much hard work and menial tasks they had to complete as an apprentice.
Profile M WS BS S T W I A LD Engineer 3 6 2(5) 5 4 3 3 3 9
Weapons/Armour: Engineers are armed with double handed hammers and wear heavy armour.
Magic Items: Engineer can have 2 runic magic items which must be chosen from the forge runes (look in section new runes in this site).
Special rules: When an engineer is present in your army for all misfire rolls you get plus one to your dice roll.
An engineer can man any warmachine (as if he was all the crew). When maning a warmachine he gets 5 BS.
NOTE:Instead you could use these rules submitted by Szaman2 for your engineers.
Engineeres are good idea, but I used them as champion characters included in cost of warmachine. I allwoed only one engineer per machine. They allowed you to shorten the time of repairs after the misfire (ie if you rolled 2 or 3 you still could shoot next turn), and also added 1 to misfire rolls (so the mashine blows up only on 1). One engineer operating mashine by himsef is again quite unrealistic. He would have to ccleen the barrel, put the gunpowder, put the cannonbal, change the fuse, find the target, and aim the hellishly heavy cannon by himself in couple of seconds. It's really not so easy...