Neat railroad and you could

Neat railroad and you could easily choose from a variety of eras: early MM with the black geeps and F units (and excursion trains - oh! and the ex-BN SD-24's), the blue and orange era or the new G&W era. I've ridden the line and it is extremely scenic. 

Nice plan

I like the plan.  Mainline through staging, branch for cement plant, branch to Woodsboro.  I did a little googling and satellite view surfing - nice choice of prototype.  Looks like a lumber outfit and a farm coop in Woodsboro, if you tweak reality a little to keep them RR served that would be pretty cool, and that quarry is huge.  If you flipped the prorotype layout to put the quarry on the aisle side of the track that would make for a pretty interesting scene.  And that cement plant looks like in addition to shipping out cement in hoppers they also load out boxcars - perhaps bagged cement?

HO scale diesels are indeed easy to get good performance out of.  One neat thing about modeling present day is you can go see things in person, or at least see a lot of photos and videos from others who have, and it does look like there are plenty of both.

I guess my only comment on the plan is to consider another staging track or two.  If the prototype only runs a single train in and out of Union Bridge in each direction each day the two tracks you have will be enough, but unless you’re convinced that’s the case and like that operating scheme another track or two in staging will give you more options.

Staging

Looks like a nice plan, two comments on staging.

First, as stated more staging is better, although being a shortline, you wouldn't have as many through freights, more staging allows cars to be "rotated" out of action more easily or adding another train.

Second, consider access to the staging tracks, hidden staging means you can't reach them, you can't see them to verify a consist, you can't reach them to swap out loads for empties.  It looks like you might have duck under access, so that might not be a problem.

One extra staging track would allow you to run an EWD and WWD through freight that sets out at Union Bridge (to feed the local that works the Woodsboro branch) and then have a turn that serves the cement plant. 

Two extra staging tracks would allow you to keep a through track open to allow running power from one end of a train to the other to "turn" the train.

Woodsboro

Nevin

Great idea. I'm working on a diorama based around Woodsboro Station as it was back around 1900. So far I've scratch-built the station and the N.Z. Cramer hardware store across the street. Next up the old mill that is directly opposite the station. Maybe someday I'll actually make a layout simulating the old run from the PA border down to Frederick.  Good luck with your project.

Alex (who actually models Nevada 1890s: https://esprrblog.wordpress.com

Here's a look at the builds.

I've seen those buildings on Google Earth!

Alex:

I've seen those buildings on Google Earth and I will have to build all three for this layout.  It is interesting to see how they little they have changed over 120 years.  I used to model Nevada around 1915.  - Nevin 

I Actually Live Not Far From There

The Maryland Midland is a really cool railroad with some great equipment over the years (including a rare Whitcomb 65-ton center-cab in the beginning), some painted in its nifty orange and blue while recently is has transitioned to the seemingly-ubiquious orange and yellow of Genesee and Wyoming.

As far as I know, operationally, the Maryland Midland is primarily focused on the cement works at Union Bridge. 6 days a week the Maryland Midland and CSX interchange cars at Highfield. Those trains are usually no less than 20 cars, mostly cement hoppers marked LEHX for Lehigh Cement (oftentimes former Maryland Midland hoppers just with a different reporting mark) or carrying the Maryland Midland reporting mark of MMID. The trains nearly always have a few center-beam flatcars too, for NVR Building Products in Thurmont. I believe you are correct in the lack of present traffic to Woodsboro. I have no knowledge about the traffic interchanges at Emory Grove.

The plan looks good, I am assuming that, like the prototype, the primary industry is Lehigh Cement. Sadly at least at present Lehigh Cement does not send out bagged cement, only bulk in their fleet or MMID's fleet of hoppers. It might also be interesting if you take some modellers's license and work a small interchange with the Walkersville Southern at Woodsboro. After all, even a tourist railroad may need to interchange a car or two once in a while.

Lehigh Cement Switcher?

The track layout visible in the google satellite view at Lehigh Cement suggests that they have an in plant switcher, and indeed there is visible what looks like it could be an SW or NW (or something about that size) switcher at the edge of the paved area near the silos.  There are a couple interesting things about the track arrangement.  First, there’s the 4 track yard just past the plant - I’d guess the Maryland Midland pulls loads and sets out empties there.  And second is the track arrangement around the silos - specifically the track that goes through a little shed on the west side of the silos goes up through a switch with just enough tail track for a single car, and the other side of the switch connects to the tracks that go under the silos.  My guess would be some sort of gravity assist switching going on there where a car is pulled through a loading track, rolls to the tail, and then back down the track to the side.  It would be interesting to know if that’s still in use.

Anyway, depending on how you want to run your railroad having an in plant switcher could be an operational plus.  Might be worth thinking about, a couple tweaks to the Lehigh Cement part of the plan now might make that significantly more interesting.

The modern day advantage

The advantage to doing a modern day layout would be that less equipment is needed and perhaps fewer structures.  You have an advantage in that the Union Bridge depot remains unlike a lot of other modern shortlines.  You could backdate the layout to WM as time passes. 

Last year I was in MD and PA looking for a possible WM town that would be nice to model but I didn't go to Union Bridge since I knew the museum was closed.

CSX came by while I was at Mainline Hobbies in Blue Ridge Summit.  Three units and a short train.

If you needed another industry you could "move" the really neat feed mill near Quinsonia.

Robert