
I started off with USPS corrugated, cut to shape and built up in layers for depth:

After cutting out the door/windows/openings, I used some embossers I found at Michael's to scribe some stonework onto the face of the corrugated. I did this for all four sides, then gave them a thin overspray of some gray primer:

After the primer dried, I gave each side a couple of coats of gloss enamel. I had a bit of a problem with crazing on the second coat, and places where I punctured the paper with the embossers didn't fill very nicely (I was counting on some capillary action that didn't happen):

My inclination was to remake sides where I punctured the paper, but then I decided not to, figuring the deeper marks simply added to the texture, and some of it was covered by signage or the striping (automotive detailing tape). I pressed on, completing the four sides and two interior walls for the tunnel bit:

The Marklin station I used for inspiration had no interior walls for the tunnel/atrium, but I went ahead and made a pair thinking it would add to the finished appearance. Here I added entrances for a book stall and a parcel office to go with the ticket and telegraph offices on the front. For the book stall, I scanned a bit of lithography I have from a Hornby station, and pasted that in to the window opening. Being on the interior wall, no one will likely see it, but I'm hopeful it might illuminate when I add the interior lights.
Window and door frames I cut from cardstock and painted using some good quality craft paint. I used some sheets of acetate for window glazing, shot with clear matte on one side to give it a frosted appearance. The frames and glazing I cemented into place using Loctite GO2 glue, a personal favorite. Once this was done, I made a base structure for the platform roof, then assembled the bottom half of the structure using basswood and a few pieces of corrugated to square it up, one of which formed the ceiling of the tunnel/atrium bit:

Next I made a pair of gable-ends for a lift-off roof, held together with more basswood/matt-board stringers. The gables were built up using corrugated and a bit of matt-board, then painted using more of the gloss spray-paint. I screwed in a single E10 cleat-socket that I'll wire up later, hoping it provides enough light for the interior:

I made a couple of roof panels using some cereal box card-board and a piece of embossed paper purchased at Michael's that looked a bit like scalloped shingles (seen in the picture above lying on the paper cutter). The embossed paper had some sort of glitter applied to it; I lightly sanded this to remove as much as possible, than gave it a mottled paint job using gray paint, along with a dusting of the green and brown from the sides, all topped with an overspray of clear gloss.
For the platform roof, I made a rudimentary structure which I covered with one-sided corrugated I got from my good friend Howard Lamey. This stuff is brilliant, replicating the look of corrugated roofing perfectly. I gave that a shot of "steel" paint, washed it with some diluted black acrylic, a shot of clear gloss lacquer, than cemented the whole thing to the back of the station using more Titebond and a couple of straight pins for temporary fasteners.
The chimneys were fashioned from some matt-board cut to shape, covered with some hand-drawn brick paper, with tops made from a piece of matt board and a couple bits of dowel (painted terracotta using some decent craft paint). They were each give a blast of clear-gloss spray lacquer (although it didn't dry with much luster).
I then moved on to making a base, cobbled together from white pine and poplar scraps found in the shop:

I used 1/4-inch basswood to build up some steps, than gave the whole thing a coat of acrylic model paint (Howard Hues "concrete", no. 1106). For the edges, I printed some gray stone paper on cardstock (from the Tribute to Tinplate site), gave it a dusting overspray of some light brown, than cut it to length and height and cemented it on. Once dry, I gave the whole thing an overspray of clear satin lacquer:

Stanchions were from my model ship bit box. I had some brass rod I was going to use for railing, but it seemed too malleable (little hands were going to have it all bent up), so I opted for an old favorite, carbon-steel guitar "string". No one's going to bend that, at least not easily. I glued the stanchions in with more GO2, than strung the wire railing. Base done, I wanted to make a little manual station signal for the end of the platform.
The signal is made from a short length of dowel, a sliver of aluminum cut from an old foot-plate for a door, a bicycle spoke cut to length (with a 90-degree bend at the bottom), and a small bolt, nut, and washer to hold the whole thing together. Three holes were drilled in the dowel so that the semaphore could be positioned for stop, slow-down-for-train-orders, or proceed-without-stopping. The inspiration for this came from an old JEP toy signal I have seen. Here are some of the bits I used on an earlier project to make a mock-up:

So here's a shot of the original tin Marklin station:

And here's a few shots of my cardboard/paper/wood version:




You'll notice I left off that telegraph wire structure at the top of the original, although I have a few repro ceramic insulators that could be used in fabricating on. Maybe later.
That's about it. Took freakin' forever, but it was a fun project for what I hope/pray is the tail-end of Covid. I still need to finish wiring the electrics, the components for which I now have in hand. It should make for a decent addition to the clockwork display planned for next Christmas.