Alco S1 Switcher Narrow Radiator Shutters

3D Printed Narrow Shutters


NE Model Works has developed Alco S1 switcher narrow radiator shutters to replace the stock wide shutters on the Proto 2000 S1 switcher. The narrow shutters are printed on an Elegoo Saturn mSLA resin printer.


When the New Haven Railroad ordered Alco S1 switchers before and during the Second World War the units were built with narrow radiator shutters. The switchers delivered after the War were built with wide shutters.

The first 40 S1 switchers, numbers 0931-0970, were built with narrow shutters. The remaining switchers, numbers 0971-0995, were built with wide shutters. If you’re modeling numbers 0931-0970 you should replace the wide radiator shutters on the Proto 2000 S1 model with the 3D printed narrow shutters.

Narrow Shutters on S1 0940

Model Narrow Shutters Design

Bill Chapin asked if I could design some narrow radiator shutters to replace the wide shutters on the Proto 2000 S1. Bill also told me that I could find photos of the narrow shutters in New Haven Diesel Locomotives Volume 1 Switchers & Road Switchers by Liljestrand & Sweetland. I already had the book in my collection.

I decided I wanted to make the narrow shutters piece with a thin flange around the edges. The flange would cover any roughness around the opening left after removing the original shutters from the Proto 2000 shell.

Then I counted the number of shutters and divided the distance between the frame by the number of shutters so I could mark guide lines at the centerlines of the gap between each of the shutters. Then I added a groove of reasonable width and depth on each of these guide lines to simulate the individual shutters.

Finally I added the small horizontal bar between the side frames and some small supports behind it. Some photos later found showed the bar was actually a thin metal bar with a “Z” shape at each end where it mounted to the frame. I left it as a solid bar so it could be 3D printed.

NE Model Works sells the narrow shutters for $15 for a pair. Shipping is $6 for USPS First Class. Please contact me with any questions or to order.

How to Install 3D Printed Narrow Shutters

Start by drilling out the original wide shutters inside the raised frame.

Then use a small saw to cut away the original wide shutters.

After sawing away the original wide shutters.

Then file the opening smooth so the narrow shutters fit. You may need to sand or file the printed part also to make it fit  inside the opening.

Using a chisel blade remove the raised flange from the original shutters. Be careful not to remove material outside the flange. Continue to remove material until the flange on the printed part sits flush on the shell without gaps.

New printed narrow shutter installed.


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