In the attached picture, below the signals is a round sign with the letter D. I see this all along the right of way and was wondering if anyone knows what this means. Thanks.
If I were to be a smart-alec (please, don't check with my wife) I'd say the "D" means "Duck". However, poking around a bit, I think it might be an indicator for the type of signal. You don't indicate the number of lines under the bridge, but I'm going to assume 2. If that's the case, the "D" might indicate that this is a 3-color light (one, two, or three - but given that there are 3 heads above, I chose 3). So, instead of each head controlling a track, the three in the stack should be taken as one signal. D = 1,2 or 3 color SA = Searchlight type G = 1 or 3 color Why teh B&O (or the Pensy) can't settle on a single type is beyond me. The darn things aren't THAT expensive.
There are speed boards that post the maximum track speed just like on the road. There are whistle posts and clearance signs and signs for special situations as well.
D is an indicator for trains that routinely stop in the block that the next signal must be approached prepared to stop. They are "delay-in-block" signs. Mostly applies to passenger trains. Is there a station in the vicinity of these signals?
