British Expats - Railway Signalling Design Engineer IRSE

I didn't want to hijack someone elses thread and I've seen a few about railway but hoping someone can help.

Me and my wife are considering emigrating having been to Australia numerous times. We are both mid 30's, no kids and mortgage paid off in UK so it's easy to rent out our property and we also have savings.

My wife is likely to be the main earner as she is an IRSE Principles Signalling Design Engineer and works for a rail company in the UK with over 15 years experience and qualifications.

There seems to be plenty of opportunities around Melbourne area (and we have cousins in Patterson Lakes) so it's one consideration but I wondered if anyone 'in the know' working in any railway companies could give an idea of salary, where the main work is based (not just in Melbourne but in the whole of Oz). NZ doesn't seem to have the opportunities Oz does. I also wondered if relocation costs are negotiable and what the clauses are eg time spent with employer etc...

I'm working with the Ministry of Justice and have a long history in Probation and rehabilitation programmes with high risk men but the salary isn't great. I'm also self employment freelance as a blogger which I could do anywhere but it would be my wife that initially would be working and I'm hoping it wouldn't be an issue if I didn't initially work, as in by an employer initially as I'm not sure I want to continue working in corrections!

Thanks for any help and suggestions.