railroad passengers and then only when the coach windows are clean enough to see
through. (This MBTA’s finances.)
I am modeling Rowley and Newbury- port on my HO scale B&M Eastern Route layout, and I wanted to include the Route 1-A bridge as a scene divider and photographic prop. There are a number of commercial arch and beam bridge kits available in HO scale. How- ever, duplicating the prototype’s skew was going to require at least some scratchbuilding.
The 1931 reinforced concrete beam bridge was added alongside the original concrete arch bridge. This view of the underside of both spans (above) shows the resulting odd appear- ance from below. The newer portion had steel plates applied over the track center line to protect the concrete from steam locomotive exhaust. The south side is shown below.
I visited Rowley to take measure- ments and photographs. Working alone, I used a 25-foot tape measure in lieu of a plumb bob to get the basic arch and beam bridge dimensions. A real plumb bob, a longer tape and a helper would have made it easier. I tacked prints of my pictures over the layout and considered how to proceed. My location could accommodate the bridge and its approach fills, but at 45 feet wide the prototype road was a sub- stantial highway. With the skew an un- compressed HO scale bridge would take up 17 inches of track, which is more than I had available. Experi- menting with HO vehicles and card- board mockups, I compromised on com- pressing the road to a 25 scale foot width. This is wide enough that the presence of vehicles doesn’t make it look like a country lane. It’s also wide enough to barely justify the two paral- lel bridge spans.
The skewed arch I started by building a “sub-road-
The template for the arch is shown next to the styrene cut for it. Because the length is less on the model, the arch looks higher. Even so, the height was reduced a little.
the south side of the arch they built a new bridge using reinforced concrete beams. Sets of supporting columns straddling the tracks carried the cen- ter span. The shorter approach spans were supported by abutments buried in the approach fills, avoiding con- struction of new wing retaining walls. In 2014,
the 1907/1931-vintage
bridge still carries Massachusetts Route 1-A over the Massachusetts Bay Transportation Authority’s Newbury- port commuter rail line, but very few drivers notice the mix of old and new. The concrete balustrade is arranged dif- ferently on the north and south sides, but the seam between the spans is in- visible. The history is only visible to
RAILROAD MODEL CRAFTSMAN
way” of ¹₂″ plywood for the highway from the backdrop to the fascia. I cut the strip an inch wider than the planned road and supported it on ris- ers against the underside of the main- line’s plywood sub-roadbed. This gave me a solid base on which to form the arch and assemble the bridge. Next, I made a template for the arch out of shirt cardboard. I got the basic dimensions by using an NMRA clear- ance gauge and developed the shape of the arch using a French curve and compass. Since my bridge is also on a curve, I had to make the crown of the arch flatter than the prototype’s to gain clearance. After I cut the template out, I cleaned up the edges.
I traced the template onto .020″ styrene sheet and cut out two arch sides. Using pins, clamps and wood blocks, I located the sides in their final positions on the plywood base. Then I formed another .020″ styrene sheet to make the inner surface of the arch, holding it against the sides with more pins and wood blocks. After checking clearances one more time, I filed a
47 varies with the
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