I will have to get 2 boxes of Straight in a month or 2. So got the engine running on a rough around 20 foot/piece circle. What maintence does the engine require?
All the points made by PhilP above can be taken as a good plan, especially for a new loco. As I run all my stuff outside, on tracks shared with live-steamers, a good wheel-cleaning about once a year is all I find necessary. Tear-down, for me, with around twenty electric locos, has never been necessary unless I'm replacing a gear - some of my electric locomotives date from the late '90s.
A DROP of light oil on the wheel bearings now and then is a good idea, and, of course, keeping it looking respectable is always a plan, unless, of course, you like your models to look like something that our Mexican friends would put on the junk-line.
Most of the Spectrum range of Bachmann models in 1/20.3 Colorado NG scale need careful looking-at. The Shays, Heislers and even the little Climax are all very complex scale models with many moving parts, and require - especially the Shays - a variety of plastic-compatible lubricants of differing grades - LaBelle make a full set for this purpose.
As for reliability well, many folks here have heard about my USA Trains GP9 that took to the mainline one summer's day back in 2001, having been inadvertently 'energised' by a well-meaning neighbour. When we came back from visiting my family in Canada, Mrs tac got into the house first and was amazed to see the loco, with five cars and a caboose in tow, merrily trundling - quite slowly - around our little backyard track. It had been doing so, rain or shine, since the day after we had left home - a total of twenty days. Apart from needing a good clean-up - it was liberally sprinkled with bird cr- droppings - and new traction tyres, it was in excellent condition. When I took it to pieces to replace the wheels [I'd decided that it deserved at least that] and give it a good wash and brush-up, it looked, and performed, as good as new.
I wrote Charles Ro, telling him the story, in the hope that it might engender a bit of publicity for him to beat Lewis Polk of Aristocraft over the head, but never heard back.
I've just leapt out of my study and taken this pic for you, so you can see how it looks now, over twenty years later and full of genuine miles of running...