Take a look at the Conway locomotive. A friend has one, which we took out last New Years day (look for "Conway Locomotive Canada" on youtube, and you'll find it).
It's simple, surprisingly light, and more than enough oomph for the task at hand. I really like it.
I do have a Tich, which IMHO is a fantastic locomotive, but do understand that others may think it's too small.
For me, either you go for a large 7-1/4" locomotive, or a smaller 3-1/2"; I don't understand 5" gauge.
(smaller 3-1/2" – easy to transport/manhandle, larger 7-1/4 – the "appeal of the large"; 5" – big enough to be a pain to manhandle, but a "wannabe" 7-1/4" – but that's just my opinion – yours may differ)
John — http://cnc-for-model-engineers.blogspot.com
Edited By John Alexander Stewart on 16/01/2014 13:00:22