If all the insulator does is isolate the spur from the main track, then no equipment bungalow would be needed. The spur track doesn;t trigger anything.
I found an insulated rail joint (orange plastic, like the old Atlas insulated joiners) in the closure rail of a turnout leading to a spur alongside a warehouse. As you said, nothing else nearby - except a grade crossing with lights and gates about 100 feet away from the points.
My somewhat educated guess is that the object is to prevent setting the points to the spur from shorting the detection circuit and lowering the gates.
Chuck (Modeling Central Japan in September, 1964 - railfanning Clark County, NV)
The strangest thing is there's no equipment shed in any reasonable distance. The whole spur is rather interesting. Its something like 2 miles long and has...geez nine grade crossings of various types of flashers, arms, or nothing at all.
One thing to do is to find where the other end of each of the insulated block rails is. Then, since you've got an electrically isolated section of rail, you should find a wire attached that goes "somewhere". It likely leads to a large normally aluminum painted box full of electrical stuff. Also, that box will likely have a lead connected over to the "ground" rail. For short runs, anyway, the wires will probably be underground.
Ed
Next time I walk past there, I'm going to have to inspect more around the area and see if I can find anything else more clue-like.
Yep, insulated joint for the end of a track circuit or block.
Chris van der Heide
My Algoma Central Railway Modeling Blog
It looks like two insulated rail joints and two bonded ones.
The purpose is for track detection. Just how it is used is not apparent, but your speculations make sense.
There's an out of service spur that loops through Alexandria VA that runs along a bike trail. Given that the tracks are completely and unquestionably out of service, I tend to walk in the grass along them instead of on the bike trail. Yesterday, I noticed something I hadn't noticed before.
Off of the spur, there's two turnouts leading into the equally out of service power plant on the waterfront. One of them is about 30 feet from a grade crossing south of this point. I didn't inspect the other turnout to the north. At no other point south of here were there any of these "devices." They're wood coated in what appeared to be fiberglass.
My guess is that these are designed or intended to keep the in plant switchers from tripping the grade crossing flashers and gates? I also noticed that from this point on, all the joints had wires joining the rail sections. Also, assuming this is related to the three grade crossings south of this location?