Three Dash 8's coupled together.  Actually this could apply to any type of loco but I chose the Dash 8's.  Two of the locos were made by the same creator and the third by a different person.  Getting these three locos to come close to the speed limit whether it be 25 mph or 65 mph is not possible.  I know, different engine specs for the third loco.  When lashing locos together I'm always aware that I need to use the same creator.  Is there a way around this without changing the engine specs and having just one spec for each type of loco?  Hope I'm not opening a can of worms for me.  Thanks.