First of all, welcome to the forum. I don't know how much experience you have with online discussion forums, but I can assure you this one is among the friendliest and most civil discussion groups on the internet (I enjoy a couple political boards that are far from civil!). So, congratulations on finding this place!
I think this is a great hobby to keep your hands busy and your mind flexible. You really could make the case for any hobby that there are aspects or specialties for everyone, but I think the model railroad hobby accomodates more interests than most. Interested in electronics? Got it. Not interested in electronics? You can buy it ready to plug in. Interested in scratchbuilding? Got it. Painting and weathering? Got it. Not interested in any of these, but just want to run your models? You can do that, too, and still have custom painted, weathered, kitbashed or scratchbuilt models (ebay is a wonderful thing).
You mentioned being a heavy truck mechanic. I wonder if you might also be interested in the vehicles side of the hobby. To most, the vehicles are no more than scenery items that decorate the layout like a snap-together station house. But to a few of us, the vehicle modeling is as important as the train modeling and to others, the trains don't even enter into the equation. I'd like you to take a look at the work of Joe Enriquez to see what can be done with scratchbuilding and extensive knowledge of the modeling subject (Joe's a heavy equipment operator, so he's around big trucks quite a bit):
http://eex-joe.fotki.com/
Take a look at Miss Sally, the Kenworth W900L, and remember, this is HO scale meaning the model is about three inches long.
You should also sign up with the
HO vehicles yahoo group and the
87 scale cars yahoo group for more information on this particular aspect of the model railroad hobby. I can tell you right off, that at least one member of the HO vehicles group, Lynne from Colorado, is in a similar situation as yourself, and judging by the results of her efforts, HO vehicle modeling has been quite theraputic.
Back to the railroad part of the hobby... I think the thing that separates this hobby from most modeling hobbies is the ability to detail models to the hilt, and operate them with incredible realism. For example, one of my uncles has long been a skilled aircraft modeler, making 1/144 scale models of airliners look like the real thing scaled down. Amazing models to behold. Another of my uncles (interestingly enough, he was paralyzed while working for the railroad and got started as part of his therapy) scratchbuilds biplanes, very, very large aircraft that operate by radio control. The one uncle who builds 1/144 scale aircraft has these amazing models that sit on display shelves and get dusted once a week. And that's the only movement they will see. The other uncle makes these incredible flying machines with nearly every part fabricated by his hands, but some concessions must be made to actually operate the aircraft, so to a certain extent, you can always tell they are models. The same is true of radio controlled NASCAR, truck or ship models, by and large. But with railroad models, you can have your cake and eat it, too.
I enjoy building models more than anything else in this hobby. From creating the CAD drawings to cutting sheet plastic to painting and weathering the models, I get great deal of satisfaction out of each project. But putting the models on the track to let them run around just doesn't do much for me. Now, put a
timesaver layout in front of me, and you won't be able to get my attention for a long time. Electronics? Not for me. I can install batteries in a toy and string Christmas lights, but that's about it. But that's alright, because I know a few people who can take care of that for me, if I build a kit or two for them or paint a locomotive for them.
Like I said, there are many specialties in this hobby, and most of us are eager to help each other out. This discussion group is a great example of that. It's part help desk, part support group, part sounding board and part show-and-tell stage and perhaps even part barber shop or coffee house. There's room for everyone here, so join in the fun.