Collection

Frank G. Zahn Railroad Photographs

4,811 photographs from the Frank G. Zahn Railroad Photograph Collection documenting Pennsylvania railroads from the 1930s through the 1990s.

CLIP Analysis Note

Each photograph was classified into visual categories using OpenAI's CLIP vision model (clip-vit-base-patch32), run entirely on local hardware. No images were sent to cloud services or external APIs — the model was downloaded and executed on-premises, ensuring that all archival materials remained under institutional control throughout the analysis pipeline. The model compared each image against 17 descriptive prompts and assigned the top 4 matching tags.

10 Visual Categories

CLIP identified 10 categories across 4,811 photographs. Six sample images are shown for each.

Steam Locomotives

2420 items classified by CLIP

Pennsylvania Railroad 6921 train

1956-12-20 · Zahn, Frank G., 1925-2008;

steam locomotivefreight trainopen trackpassenger train

Reading Railroad 1153 locomotive

1934-04-29 · Zahn, Frank G., 1925-2008;

diesel locomotivesteam locomotivefreight trainelectric locomotive

Pennsylvania Railroad 4270 locomotive

1956-04 · Zahn, Frank G., 1925-2008;

steam locomotivefreight traindiesel locomotivepassenger train

Pennsylvania Railroad 5436 train

1949-09-15 · Zahn, Frank G., 1925-2008;

steam locomotivefreight trainmid-centurydiesel locomotive

Strasburg Railroad 1223 train

1973-06-07 · Zahn, Frank G., 1925-2008;

freight trainopen trackpassenger trainsteam locomotive

Strasburg Railroad 7002 train

1983-08-31 · Zahn, Frank G., 1925-2008;

steam locomotivediesel locomotivemid-centuryclose-up detail

Diesel Locomotives

3184 items classified by CLIP

Pennsylvania Railroad 2000 train

1961-03-26 · Zahn, Frank G., 1925-2008;

diesel locomotiveelectric locomotivefreight trainpassenger train

Reading Railroad 1153 locomotive

1934-04-29 · Zahn, Frank G., 1925-2008;

diesel locomotivesteam locomotivefreight trainelectric locomotive

Pennsylvania Railroad 4270 locomotive

1956-04 · Zahn, Frank G., 1925-2008;

steam locomotivefreight traindiesel locomotivepassenger train

Amtrak 304-264 train

1993-08 · Zahn, Frank G., 1925-2008;

electric locomotivepassenger traindiesel locomotivefreight train

Pennsylvania Railroad 5436 train

1949-09-15 · Zahn, Frank G., 1925-2008;

steam locomotivefreight trainmid-centurydiesel locomotive

Strasburg Railroad 7002 train

1983-08-31 · Zahn, Frank G., 1925-2008;

steam locomotivediesel locomotivemid-centuryclose-up detail

Electric Locomotives

1942 items classified by CLIP

Pennsylvania Railroad 6913 train

1967-07-15 · Zahn, Frank G., 1925-2008;

freight trainrail yardelectric locomotiveyard / switching

Pennsylvania Railroad 2000 train

1961-03-26 · Zahn, Frank G., 1925-2008;

diesel locomotiveelectric locomotivefreight trainpassenger train

Reading Railroad 1153 locomotive

1934-04-29 · Zahn, Frank G., 1925-2008;

diesel locomotivesteam locomotivefreight trainelectric locomotive

Amtrak 304-264 train

1993-08 · Zahn, Frank G., 1925-2008;

electric locomotivepassenger traindiesel locomotivefreight train

Pennsylvania Railroad 6744 train

1956-07-01 · Zahn, Frank G., 1925-2008;

steam locomotivefreight traindiesel locomotiveelectric locomotive

Erie-Lackawanna 7121-34 train

1973-07-18 · Zahn, Frank G., 1925-2008;

freight trainelectric locomotivediesel locomotivecolor photo

Passenger Trains

1613 items classified by CLIP