I'd add that being the guy that's "always there" helps. Not always there in sitting at your desk for 100 hours a week, but when called on to take something on, stepping up and saying, "I'll give it a shot." We had an engineer quick abruptly and leave a project prior to completion. While one of the more senior engineers took over as the lead, I was able to step in and pull some of the weight with the less technical aspects. I believe it was very much appreciated and when, after weeks of stressing, those of us involved managed to get everything to turn out alright (even if over-budget), I think the efforts of all involved were much appreciated by management.
I guess the short of it is, figure out what your boss/others are struggling with and get in and help. As I see it, that IS the job of the younger engineers, to make senior engineers/engineering managers life a little easier. Chances are before the younger engineer was hired, they managed to get by, although probably with more stress. Therefore, the young engineer's job is to relieve stress when possible and learn from it. Often the projects that cause the most stress have the most "training" value.
-- MechEng2005