The Philadelphia and Western Railway faced serious competition when, in 1930, both the Reading
and Pennsylvania Railroads electrified their commuter services between Norristown and
Philadelphia. To counter this improved service, the P&W bought ten state-of-the-art
aluminum Bullet cars in 1931. Designed in a wind tunnel, they regularly reached eighty
mph in regular service. So robust was their design that they were to remain in service
on the Norristown High-Speed line for sixty years.
| This 3D computer model started out in AutoCAD. First, 2D plans and elevations
were drafted, based on blueprints of the Bullet car. The CAD drawing was
built from the dimensions on the drawing, with subtle details filled in
by tracing over the portions of the plan with a digitizer. Because the point
of this was to generate an accurate drawing, a scanner was not used. |
| The accurate 2D CAD drawing was then used as the basis for a 3D CAD model.
All 3D geometry was built inside AutoCAD Release 12. The base AutoCAD package,
with millions of installations worldwide, has actually had full 3D capability
since the October 1988 unveiling of Release 10. DDvpoint and the
UCS command are the main gateways from 2D to 3D in AutoCAD. Once there,
five commands are all that is needed to generate any surface. Here, the
Edgesurf command was used to generate the sleek Bullet's roof. |
| 3D Studio was used to render the AutoCAD-generated 3D model. Since its
inception, 3D Studio has been able to read and write DXF files that contain
3D geometry. AutoCAD R13 was the first release able to read and write 3DS
files. Windows-NT based 3D Studio MAX 1.1 had the ability to read and write
3D AutoCAD drawings directly. At the time it was hoped that Autodesk was
working toward a single, unified file. |
| This viaduct was built over the Schuylkill River at Norristown in 1912
to carry the P&W tracks over the river, one canal, and three railroads.
It is still in use today. Lacking plans for the structure, data was gathered
by visiting the bridge, carefully measuring the spans and documenting details
with photographs. Like the Bullet car, the geometry was modeled in AutoCAD
R12. Because of its repetitive structure, extensive use was made of the
mirror and array commands. |
This photo of the viaduct, with a Bullet car rolling over it, was taken from the nearby
Dekalb Street bridge in the spring of 1979. Though already almost fifty years old,
the Bullets would soldier on for another ten years. That last decade pushed the limits
of the Bullets and the Strafford cars too far, with several collisions and fires. One
passenger was killed when a Strafford car lost brakes and rammed 69th Street Terminal, ending
up inside the waiting room. The line was almost closed down in the early 1990's, before
used Chicago El cars were brought in, while the new N5 cars were being built.
Mike Szilagyi photo
More about the Bullet cars.
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