I've started sketching out some ideas for the layout focusing on Baltimore.
Here's what I'm thinking about doing for the Mount Vernon area. This is my first (incredibly not to scale) idea.
The tracks toward the bottom head off toward the rest of the layout, generally heading North to York and Harrisburg.
At the top, the double track heads into staging, representing Baltimore's Bayview Yard, Washington DC and Potomac Yard in NoVA.
The "branch" that heads off and joins back up is actually the line that would head to DC, theoretically splitting off and heading into a tunnel (which would've met up with NEC south of the B&P tunnel). In this sketch it loops back into the mains heading for staging, but this would be hidden by tall structures, so would be "off scene".
The double track main on the right is the "passenger main", which would tie in directly with the NEC at Baltimore's Penn Station. This track would be bidirectionally signaled and would see MARC commuter service (a few trains in the AM and PM) and the Amtrak Susquehanna Service trains (2 each way each day). Theoretically, this track would tie in South of Penn Station and allow access to the station.
The double track main on the left is the "freight main", over which traffic for Bayview Yard would travel. This would largely be for trains terminating in Baltimore, such as ENBA/BAEN, coal trains for export using the Consolidated Coal terminal and the various TV trains.
The diverging route (The DC route) would handle traffic for the south, like SEPY/PYSE and the Delaware and Hudson run-through trains. Additionally, a few coal trains for the various generating stations on the Popes Creek Branch would also take this route.
This is the actual junction where the track to DC splits off from the passenger main. There isn't a full set of crossovers here because of the proximity of the next set at CP WOOD.
Here is where traffic for the three different destinations splits, with traffic north of here running directionally on the two mains.
Additionally, this is where the crossovers into the Mount Vernon Yard are located, and the Calvert St. Industrial Track breaks off. The industrial track heads down and under the mains.
The Yard itself is a very small affair, only serving two purposes: to provide a place for SEPY to drop a block of cars for Baltimore, and a place for the local job that serves the industries along the industrial track to work out of.
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