Don't let engineers multitask, they can't and neither can you.

That's right multi tasking is wrong, don't do it.  More importantly don't let your engineers do it.
Why do I stress engineers?  Go over to your nearest engineer.  Interrupt them, I know this is a bad thing and ask them how many projects they are currently working on.  Ask them how many project items they will work on today.  Ask them how often they will swap between those tasks.
Engineers are very simple creatures.  I can say that as I am one, and have the P.Eng. to prove it.  Consider your engineer to be a precision machining center.  You would not interrupt a machining center half way through a step. Except this is what we do with engineers all the time.  Like the machining center, engineers have a set up time. An engineer’s brain may appear to be able to instantaneously swap between tasks, this however is an allusion.  The immediate “information players” that the brain uses in the frontal cortex can be changed quickly.  What takes time to reset is the links to the backup information the brain needs.  The change over appears quick, the ramping back up to speed is what takes time. 
Some very simple tasks can be multitasked, most cannot. If you want to prove this to yourself play the TOC bead game - www.wsu.edu/~engrmgmt/holt/em530/Docs/BeadExperiment.ppt

 
So do not get caught up in the trap of getting engineers (and yourself) to multitask.  Multi tasking only slows progress down and actually hinders the on time delivery of work.