I would suspect that the reason they are that way is simply that the interlocking plant dates to the pre-WWII era. Of course modifications have been made to the interlocking over time, but so far as switch heaters go, what A-2 has is basically a big set of "automatic tallow pots". Piped-in gas that has to be lit by hand, with a torch, at each outlet. With as situation like this, it's difficult to imagine that the heating system has been substantially updated since installation? I of course defer to any ferroequinologists who may be able to provide better details.
There are several more modern varieties of switch heaters available today. The typical expected installation is on a simple control point, with one heater per switch; but with a little creative custom engineering, most any of the modern stuff could be made to work on a complex plant like A-2. The real crux of the issue is: what would the point be to lay out all that money to make such a changeover? The only real difference with the modern stuff is that the operator/dispatcher can turn the heaters on/off with the push of a button. At A2, this isn't much of a concern, since you're pretty much always going to want a full-time maintainer there anyway (to quickly take care of ANY problems that crop up). Reliability certainly isn't 100% on the modern heaters, either. They still suffer common pitfalls like blown-out pilot lights, faulty thermostats, failed ignitors, failed blower fans, code-line failure, etc. etc....
I certainly advocate for the elimination of the A2 crossing in favor of a flyover. This was not my previous opinion, but however, in just the past year, it has become very apparent to me just how long-in-the-tooth that this operation has become. I have been going over A2 as either a passenger or employee for almost ten years now, and I can NEVER remember the place being as maintenance-intensive (and therefore: delay-filled) as it has been this past year. And I mean - YEAR - not just the current/past winter.
With reference to Mr. Jogden's concern : while it is rare indeed that ANY freight movement goes across A-2; there are no special equipment restrictions in place solely account of the switch heating "devices". Really, too, no matter what kind of car it is - the flames produced by the heaters will almost never reach as high as the level of the top of a wheel. While a good deal of freight used to move through this interlocking "back in the day" - mostly boxcars bound for the downtown freight houses - today, there are only two movements which are commonplace: the occasional switch of the Blommer Chocolate Co. by UPRR, and the 5-per-week switch of ADM-Ogden Ave by the NS (descendants of the PRR, which surely once held the contract for same). The only tank cars going across A-2 are the occasional cars of corn syrup.
hey there guy