This isn’t a simple map of which stations get empty and full. Rather, as DDOT’s Ralph Burns explained at the recent meeting, DDOT weighed the amount of time it’s empty and full, the total traffic, and an estimate of the revenue from that station. Blue stations have high usage and/or revenue and more time empty and full, while red stations are the opposite. Yellow is the “sweet spot” where revenues are good but the station isn’t too popular that it’s often unavailable.
There’s a dominant pattern here, but also some interesting idiosyncratic elements. The station just south of Union Station, for example, is oversubscribed while the one just east of it is underused. I think the problem here is specifically that the underutilized station is quite hard to see; when I needed to dock there for the first time I had to get an Amtrak cop to direct me.
The politics of the thing would seem to point toward building more stations in the sparsely-stationed periphery, but the actual demand patterns suggests that there’s plenty of room to build more stations in the core. I think it’s not unrealistic to hope that building more system capacity in the high-demand arc will at least marginally increase utilization of those peripheral stations to the point where it makes sense to build more of them.