I would think that generally switching into an engineering program your second year from a physics program wouldn't be that difficult; assuming that the gen. physics class doesn't have a particular registration set up for just engineering students (my school has this, they call it physics 221-223, physics for science and engineering majors, but it is actually the same class as the general physics with calculus course (it is actually at the same time by the same teacher in the same room), however, it is for 1 less credit and as such students from that registration are not expected to stay the whole time, but are allowed if they wish).
The best thing to do is to look up the engineering school's requirements and make sure you are fitting all of them in your physics program. But I would generally, forsee little issue with switching the programs. At least that early on.