Great Northern Railway Historical Society Blueprint Collection JSBP0946, Clayton, Washington, 1919. Bridge # 20. Rearrange Undercrossing. Authorization for Expenditure 9557. Interstate Commerce Commission Account Number 6, Bridges, Trestles, and Culverts. Other ICC account descriptions: ICC Account Number 6, Bridge.

Great Northern Engineering Drawing: Shop Plan - Girder Span, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 13, undated.

Great Northern Engineering Drawing: Shop Plan - Girder Beams, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 12, undated.

Great Northern Engineering Drawing: Shop Plan - Ball Plates, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 14, undated.

Great Northern Engineering Drawing: Miscellaneous Steel Details, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 8, undated.

Great Northern Engineering Drawing: Layout, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 3, 1938.

Great Northern Engineering Drawing: Girder Spans, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 7, undated.

Great Northern Engineering Drawing: Drainage Details, Bridge 20 - Undercrossing, north of Clayton, Washington, Line Segment 376, Milepost 34.37. Sheet 270 - 4691 - 11, undated.