Well, I have been kicking around a bunch of ideas in my head and I thought about making a test track. I guess it would be the typical straight sections of track everyone usually sees here or there. I then thought what else would go on or into a test track. Do some have switches on them, or other things like activation switches? Could really use some opinions to tinker around with, any idea is a good one.
Thanks
Dave
Happy Hump Day 
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The command systems should be included.
An uncoupler/unloader section.
Either a transformer with meters or metering of the track.
My test track is pretty simple, 7 ft of tubular track with an insulated track section in the middle and a bumper at each end to prevent runoffs. I use whatever transformer available at the time. It is all screwed down to my work bench.
Mine's portable: 2-10" Lionel sections, 2 alligator clip wires, and a 9-volt battery. An extra section can be added if needed fir a shirt run. It's for good for testing lights and simple basics of your space is limited or you're in the go. For more serious work, I'll use the track piece with the power drop and a wall wart or the adaptor wire that I made for use with my MTH transformer and controller. It's all still portable.
TRRR
Personally, I find test tracks to be of very limited value.
I keep a couple of pieces of straight track, along with a UCS track section in one of my work desk drawers. They come out when I am testing / working on operating cars.
Otherwise, I don't use a test track.
I have a set of rollers that I use on rare occasion.
I have a simple power source installed in the area around my work desk. It's basically an LW transformer with a pair of meters (volts and amps). I also have a DC power source that is split off from the LW via a rectifier.
Most of my testing is done with a pair of test leads.
When I want to do a running test, I bring the item over to my layout.
I pretty much agree with C.W. regarding a test track - however, if you are heavily into repair and/or modifications as part of the enjoyment of this hobby, I have thought a relatively cheap and useful tool would be a digital electronic fish scale, available on your local interweb sources for $15 or less.
A small scale will allow you to detect pulling power of your locos before and after repair/modifications. Combine this with a volt meter and very importantly an ammeter, and you can paint a pretty good picture of how powerful your engine is and whether your repairs or improvements have had the desired effects!
Not for everybody, but music to my ears! 
If your layout is divided into Blocks you have as many test tracks as you do Blocks.
I have made test tracks for friends. They consist of three different radii "S" curves separated with a tangent so as to check cab/tender clearance of different equipment for different portions of their layout.
Wow, all very interesting. About pulling power, how does that translate into cars pulled? Is there an average scale of what is pulled like 2.5 pounds = x amount of freight cars, y amount of passenger cars, 2 pounds = x amount, etc., etc.?
Thanks for all the suggestions. 
Dave NYC Hudson PRR K4 posted:Wow, all very interesting. About pulling power, how does that translate into cars pulled? Is there an average scale of what is pulled like 2.5 pounds = x amount of freight cars, y amount of passenger cars, 2 pounds = x amount, etc., etc.?
Thanks for all the suggestions.
No # of cars translation possible. I have a PW crane that is about equal to 10 or maybe even 12 modern needle point bearing equipped cars in terms of friction/drag, so.... A pulling power scale would only be useful for making relative measurements on an engine, i.e. it pulled 1 lb before the wheels started to slip, but with new traction tires it now pulls 1.2 lbs, just as an example.
I have a 4 foot long test track, one track is 3 rail O scale, one is 2 rail O scale, one is HO. Alongside this is the smallest loop of HO slot car I could create. Powered by a LW transformer. I built a box based on an article in CTT years ago so I can switch between AC and DC current (for the 2rail, HO and slot car). Included is an uncoupling track to that I have never used but I had an extra one so why not.
Many good suggestions so far. Here's what I decided to do. 12ft long and easy to move.
Link to ogaugerr post on it:
https://ogrforum.com/topic/test-track-project
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