Actually on Main Street, their is an island platform and two side platforms. So cut staples mill and make all Amtrak's stop there
Which part of "you can't run the trains south of Main Street" did you not understand?
It has nothing to do with how many platforms; you can't go south from that station!
There is also the matter of ACCA yard too, but that's minor compared to the fact that you can't go south.
Do you not know Main Street Station. There are four tracks. The island platform serves the central tracks and the side platforms serve the end tracks. The long distance Amtrak's would use the tracks that go south and NN bound NER uses the other tracks. It will also be the future station for the Southeast High Speed rail which goes from DC or Hampton Roads to Jacksonville.
I know Main Street.
And again, the south bound track is either out of service or at least not up to passenger standards, I don't recall which. But the point is that you currently cannot go south no matter what track you use at that station.
Amtrak has wanted to stop the LD's at that station ever since they reopened it; but they can't because the tracks aren't usable for passenger service to reconnect with the CSX main to Florida. Until that track has been brought back to passenger standards,
Amtrak cannot run long distance trains into Main Street.
Even once those tracks are restored, Amtrak has no plans to cut Staples Mills, because again it serves the burbs and a huge amount or riders. They'll just make both stops and continue on their way.
My understanding is that there are likely to be at least some trains that will skip one stop or the other
at some point, but that is also
years down the road. IIRC, the plan is for RVM (that is, Main Street) to become the primary station in Richmond and RVR (that is, Richmond Staples Mill) to become secondary. However, RVM is
badly short on parking and is inconvenient for anyone in the northern suburbs of Richmond (in some cases, dropping RVR would make Ashland more convenient). What is likely to happen, if I had to take a guess is this: The TDX comes to pass, and it stops only at RVM (the state plans hint at this from what I've read...RVR is simply out of the way for that train). If SEHSR also gets up to the planned frequencies, you're going to have at
least 13 non-LD trains in each direction each day (3 WAS-RVM-NPN, 6 WAS-RVM-NFK, and 4 WAS-RVM-CLT), plus the 3 LD trains. Sooner or later, one or more trains will likely drop RVR as most of your connections will move downtown (which also "plugs in" to Richmond's bus network, such as it exists, a lot better) and connectivity with the TDX exists. You'll still have 7-10 trains per day at RVR at least, but depending on ridership, I can see some reduced-stop express trains cutting a bunch of intermediate stops out if demand trends upwards for long enough.
There's a longer-term obstacle to dropping RVR, though, and that is the likely long-term growth pattern of Northern VA. I suspect that as time goes by, Washington-Richmond is going to become more and more of a merged corridor along the lines of the New York-Philly situation. Yes, the distance is larger, but the area is developing a hundred years later than a lot of the NY Metro area's growth took place and in the context of both the automobile and (at least in the longer-term plans) faster trains than have ever run on many of the New York area metro lines. IIRC, there are plans out there to try and shave 10-20 minutes off of the Richmond-Washington travel time (from about two hours to somewhere around 1:40) with a series of incremental upgrades as part of the SEHSR plan. RVR isn't that badly placed to act as a suburban station if any sort of commuter system starts to build up, be it Richmond-Washington or otherwise (and I'd point out that I-295 is about as far from Washington, DC as Martinsburg, WV, which serves as a MARC terminus). If anything, I would expect a long-term trend to build towards having a couple of stations get added (look at some of VRE's plans: More stations are being looked at along the existing line to relieve parking capacity) as densities increase, albeit mainly for more commuter-style service.