When presented with the luxury of designing a new hospital (see Len's opening post) it's probably best to begin by blocking out sensible (rational, logical) clusters of functional departments:- Sterile Supplies adjacent to Theatres, ICU next to Theatres, NICU near to L&D, Radiology and CT next to A&E, Physio near to OPD etc., etc.
"Engineering" is often stuck out in a Services Building* - near to the generators and so forth. That is OK, but (as already mentioned) Biomed Services should be nearer to the users (that is, in the main clinical building), with satellite workshops scattered here and there as previously discussed.
I know that architects (especially) are usually in a hurry to develop their latest "beautiful creation", but they often need to be "managed" (restrained), and reminded by more down-to-earth (and to them, lesser) beings that we are essentially designing a place of work, rather than an art gallery.
By the way, when I say "adjacent", don't forget there may be various ways of achieving such "connectivity" - adjoining departments, corridors, and elevators (lifts) to name just a few ... as well as pneumatic tube systems (which seem to have made a bit of a comeback in recent years).
"Distribution" of supplies, patients' meals and what-have-you is another area that should be thought about early on (rather than literally being an after-thought); there are options there as well (does anyone else remember the subterranean roads with electric stores trains running around the basement at Northwick Park?).
Lastly, even at an early stage, don't forget compartmentalization of departments vis-à-vis
fire protection (and regulations) - something else best incorporated into the overall design right from the start.
See also this
ancient thread (some of the links no longer work, unfortunately).
* Also a good place to hide the Laundry, by the way.