The Interborough Rapid Transit (IRT) Powerhouse was really not on my Westside Railroad Layout to-do list. That was until a fellow modeler asked me if I could help him with a flat structure that would hide part of his staging yard. And he also pointed me to that building in the Upper West Side. I noticed it before as one of the historical buildings on Eleventh Avenue. I never bothered to look up its history, however, since it was outside of my West Chelsea layout scope. Doing a little research on the building I realized what a gem this landmark structure is.
The IRT Powerhouse was built in 1904 as one of the few visible structures of the New York City subway system above ground. The massive building housed the boilers, steam engines and generators and generated power for the city’s first subway system. It is located on Eleventh and Twelfth Avenue between West 58 and 59th Street. The proximity to the Hudson River was not a coincidence. Obviously, the best way to saturate the powerhouse’s appetite for fuel was to deliver the coal on barges to a nearby pier. In this case it was located at the foot of West 58th Street.
Building Architecture
The IRT Powerhouse is a notable example of Beaux-Arts architecture in New York City. It features classical elements, grand facades, and ornate detailing. It is characterized by its impressive brick facade, featuring pilasters and friezes with rich terra-cotta ornaments and a prominent cornice. It has a symmetrical design with rows of windows and decorative elements, giving it a sense of grandeur. The massive building is 200 feet wide along its principal elevation facing Eleventh Avenue and 800 ft long. The single story that houses the machinery is about 45 ft high while the attic is roughly 10 ft high. A twin gable roof with clerestory monitors tops the building.
Selective Compression of the Model
For the IRT Powerhouse, I secured a spot in the background on my layout plan about 7.5 by 11 inches. I had to take into account a street level track leading from the Baltimore & Ohio West 26th Street Station to the northern leg of the L-shaped layout. The large window bays on the front and side facades give the building a modular structure. Modularity greatly facilitates selective compression.
The size of the front facade let me include four of the six window bays of the prototype. The short depth only gave me room for two of the 17 window bays and for the corner section. To accommodate the thru-track, I mirrored the design so that the corner section with the freight door is on the opposite side. I accepted that loss of fidelity as the change doesn’t alter the architecture fundamentally.
Designing the Model
Once I had the layout of my selectively compressed model, I proceeded to designing the facade. A proof of concept (photo in the center above) helped me translate the complex facade into a design suitable for laser engraving and cutting. The short piece with two windows from the south facade looked stunning and exceeded my expectations. Not only did it prove to me that the design wasn’t overly complex, but it also showed that it wasn’t so difficult to replicate the beauty of that Beaux-Arts building in the Upper West Side.
The model consists of three parts: 1) the (east) front facade and the two (south and north) side facades, 2) the inner supporting structure, and 3) the roof. In a first step, I created the facade elements. With facade walls completed, I proceeded to building a supportive structure until I had a shoebox-sized model. The last step was then to create a roof structure on top of that box.
Building the Facade
The facade elements are based on a layer of 1/16″ MDF. On top of the MDF sits a 1/16″ basswood layer. The softer basswood has the surface textures like bricks and granite blocks at the bottom engraved. A layer of .015″ laser board below the MDF includes the window frames and mullions with the unusual diagonal elements. To accommodate the ornate terra-cotta elements on the pilasters, moldings, and window lintels, I used 1/16″ white acrylic sheet. This became the top layer on the engraved basswood.
All layers were engraved and cut separately and immediately primed, painted, and weathered before even assembled. This ensured a clean separation of coatings and was necessary as I was using (Tamiya) spray paint. For weathering, I used an India ink wash for the brick walls and pilasters. I also applied small amounts of PanPastel weathering powers. To enhance the contrast and to tint the dominating gray, I finally dry-brushed the surface with acrylic paint. Hidden gaps in the primary facade layers and matching tabs on the horizontal moldings ensured accurate assembly of the layers.
Facade Details
The front facade includes some additional details that I took great care to include. A large and intricate wreath made from terra-cotta is placed above each front window. My simplified and bitmap traced patterns of those wreaths don’t really adequately represent the prototype. But then again, their intricate details aren’t really visible in N scale. Similarly, the separately applied semi-circular lintels have a simple pattern engraved.
Fortunately, I had a bit more luck with the Interborough Rapid Transit Powerhouse signage above the front facade’s cornice. The lettering is large enough so that engraving it in acrylic sheet resulted in a crisp, well readable and prototypically accurate rendition.
Supporting Structure
Even though I used mostly solvent based paints and only modest amounts of iso-propyl based wash, the facade was subject to slight warping. To compensate it, I used vertical walls behind each pilaster. Tabs in the wall elements made from 1/16″ MDF interlocked with hidden gaps in basswood-MDF-laser board layers. Tightly gluing them onto the facade elements ensured almost perfectly plane surfaces.
The walls are connected by a floor and a ceiling below the attic. This creates two smaller wings behind the left and the right facade and two larger halls in the center. In reality, the building had only two large halls, the left (southern) one for the boilers and the right (northern) one for the stem engines and generators. Since I saw no easy way to include machinery, I accepted that compromise – at least for now.
Before adding the roof, I made sure to include the LEDs in the big hall’s ceiling. I soldered the LEDs to the lighting bus made of self-adhesive copper tape. A step-down circuit from 12V to 3V that I used in other buildings too will complete the lighting function.
Designing and Constructing the Roof
Many of the existing archive photos are taken from the ground and don’t show the roof construction. Fortunately, there exists a cross-section of the building from south to north that reveal quite a bit of details. The corrugated metal roof we see today must have been added more recently as part of the repurposing by ConEd. From a few photos I could infer that the original clerestory roof was covered with tiles. While I found no photos of the exterior of the larger gable (which is actually a gambrel) of the generator hall, I assumed it was different due to its smaller pitch. Instead, we do have photos from the inside of the generator house, and they show glazing for the lower roof slopes.
The roof’s construction provided me with unique opportunity to show that laws of physics and specifically laws of static forces also apply in a small scale. Using the cross–section of the building, I designed the skeletal roof structure as best as I could.
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I cut trusses of 1/16″ acrylic sheet for the two different hall ceilings. This creates a smaller gable for the left (southern) hall housing the boilers and a slightly larger gable for the right (northern) generator hall. Seven lateral double-trusses are connected and interlocked with eight longitudinal trusses. Top and bottom chords as well as cross-members are only 1 mm or slightly more than 1/32″ thick. Glued together, they create the basic shape of two longitudinal gables and a laterally connecting gable in the front with a clerestory running around the entire roof.
This was the easy part, as I now had to fit the under-roof and the roofing on top of the skeletal. To begin with, I added brick walls and windows to the clerestory, then the roofing of the roof section below. I used two layers of laser board for the roof. A thinner one for the under-roof and .035″ thick laser board with a tile pattern engraved on top. Furthermore, to create a strong bond between the tile roofing and the truss structure, I used two-component epoxy to glue. The same way I glued the tile roofing to the under-roof. The roof cladding tightly glued the skeletal structure create a compound body that is stronger than the two parts alone.
Roof Details
In the sections above the clerestory I also had to include some unique details. The left gable covering the boiler hall originally had six smoke stacks made of bricks. I only had space for one. For the smoke stack I used a product from Walthers. Not having detailed measurements for the location and height of this detail, I am not clear how prototypical my rendering is. I gave my best to remove the flash on the plastic part without destroying the brick texture. I then primed, spray-painted and weathered the stack. To insert it into the roof, I had to add a platform in the center of the gable as per prototype photos.
The gable of the roof covering the generator hall has a minimal pitch of less than 12 degrees. This renders it unsuitable for a tiled roof. In its original state until 1959, the lower slopes of the gambrel roof were glass covered. By contrast, the two top slopes that are almost horizontal were most likely covered with a light metal roofing. Photos I have consulted are inconclusive, so I chose the simplest form of a tin roof with seams.
While the completed model strongly resembles the prototype in its current state, the roof and the large protruding cornice bring it closer to the original building from before 1959. Time and again, we have proof that a model has the power to provide a good visual rendition of the past. And as a nice bonus, attempting to replicate the delicate roof structure provided interesting photo opportunities, as the photo above shows.