There was a train scene in Species. Natasha ate a female train conductor, and – I dunno, grew or morphed or something, and left behind the remnants of … a slimy cocoon-like thing. Michael Madsen and Ben Kingsley were in the movie too.
I’m pretty sure it’s Xtro, here’s the trailer. You can see most of the elements described in the OP.
Species did have a train scene but it’s not really Cronenbergesque.
There’s a Youtube review of the film that shows a “breeding pod” in the shower. Here’s a clip:
http://www.youtube.com/watch?v=tFzBFuo00iU#t=122
Yep, that’s it!
Thanks man and thanks to the mods
for leaving this open
Cold Case Files: SDMB scores a victory!
“It’s taking longer than we thought.” 
I saw Xtro years ago but the only things I remembered about it were some vague bit about eggs and that it was really bad. I googled some words from the OP and found it. I was surprised I had actually seen the movie in question.
And now, I will go back to forgetting I ever saw it. La la la.