Wednesday, April 24, 2019

Chicago Lake Street "L" over UP/C&NW and NS/Pennsy's Panhandle

(Satellite)

Around the turn of the 20th Century, Chicago had so many railroads with so many trains that streetcars and horse&wagons had to stop and wait a lot for trains. Sometimes the crossings would be blocked for a long time because a train was stopped waiting for another train at a junction to pass. So Chicago started passing city ordinances requiring the railroads to elevate their tracks to eliminate grade crossings with vehicular traffic. Some railroads were built when Western Avenue was the western boarder of Chicago. Since the railroads tended to build just outside of Chicago's boarder, there tends to be two or three railroads next to each other just west of Western Avenue. I've documented those railroads in the Western Avenue Corridor. (The specific railroads in the corridor changed as railroads entered and left the corridor.) To reduce the cost of elevating the tracks, the railroads that were adjacent to each other would sometimes hire the same contractor to do all of the railroads at once to share steel girders, abutments, and lowering the street. This also provided an economy of scale because construction equipment such as cranes and steam shovels could do all of the railroads while the equipment, and skilled laborers such as ironworkers, at the site. And since the contractor had a bigger job to do, it could afford bigger construction equipment and get the job done faster.

With that introduction, we can study an example of an elevation project.
Dave Durham posted
Lake St. Subway/ Rockwell St. Elevated/ Lake St. Elevated...1898, IRR&WC Report, Hathitrust, Unknown photographer.
I used Street Views from Google Map to see what these layers of transportation look like today.
Dennis DeBruler commented on Dave's post
Street View saves me a lot of  time and gas :-)  Looking East
Judging from the old photo, the Lake "L" used to have four tracks. https://www.google.com/maps/@41.884437,-87.6920277,3a,60y,83.96h,97.42t/data=!3m6!1e1!3m4!1slKugRaTR1BCg9xrvfxIoXQ!2e0!7i16384!8i8192
While looking for another photo, I found my photos on Lake Street including this crossing.
20171122 8108c

Dennis DeBruler commented on Dave's post
This view looking west showed me why they used the word "subway." They lowered the surface of Lake Street about five feet.
https://www.google.com/maps/@41.8844669,-87.6913021,3a,75y,257.81h,92.18t/data=!3m6!1e1!3m4!1sR52IxMcVQ7N4URNUjbvKJA!2e0!7i16384!8i8192

Dennis DeBruler commented on Dave's post
I've been studying the "L"-over-railroads-over-road crossing some more and realized that there used to be two more tracks on the east and west side of what still exists. https://www.google.com/.../data=!3m6!1e1!3m4...
Even though there are only two tracks left, there are three bridges so that an access road is part of the railroad corridor.
Note that the abutments apparently still have their original cut stone construction.
Also note that from the shared abutment and bridge girders, C&NW and Pennsy evidently paid the same contractor to elevate both railroads at the same time.
I can use this overpass to confirm that the topo maps don't accurately depict the number of tracks when there are several of them. A study of the bridge abutments shows that there used to be seven tracks over Lake Street. I've already noted that the "L" appears to have been reduced from four tracks to two tracks.
USGS, Chicago Loop, 12,000 scale
Dave's post included a second image:
2
[Details about the northern part and the southern part]




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