I have put together a short essay from my notes that I compiled for my narration on the IRM Snowflake "L" Charter and I am sharing them in hopes that you find them interesting and educational.
Snowflake Notes...The Why and Where For Chicago's Elevateds
If you've ever flown into O'Hare or Midway at night, you've marveled at the grid patterns of light, the illuminated squares, the end result of a land use policy that divided our area into square miles called sections of land. The first surveying was done in conjunction with two Indian Boundary Lines, that marked a twenty mile corridor for a planned canal in the early 1800s The north line is clearly marked by streets and crossed by the Blue line after the Jefferson Park station, but the most familiar crossing is by the Red/Purple lines just south of Howard St. Within the city limits, the south line is almost invisible, marked by a few stretches of chain link fencing and an obscure street near 127th St. If extended, it will be crossed by the Red line extension.
The sections inside the Canal lands and the sections outside on both sides of the Boundary lines were sold and then subdivided into half sections and quarter sections, even down to quarter-quarter sections...the proverbial forty acres. All the subdivisions had to be further divided into blocks, eight of 'em to a mile is the accepted standard. But if both your streets and avenues are divided like that you end up with square blocks with a big unused space in the middle. So you have to run half block streets in one direction with paralleling alleys and then there is no unused space and you have rectangular 1/2 blocks. Because streets along the section and half section lines are generally heavily trafficked arterials and more valuable, "T" alleys are formed behind them so that the lots face those valuable streets, even along diagonal alignments.
Three of the four elevated railroads chartered and constructed in Chicago; The South Side, The Metropolitan West Side, and The Northwestern were required by their franchise ordinances to only build "through the blocks." They could buy, lease, rent, a private right of way, but they could not build over streets or alleys. They could cross them, of course. If the half block streets and their accompanying alleys parallel the route, the cheapest way to go was to usually buy the back 25 ft of backyards next to the alley. If the alleys were perpendicular to the elevated, a more expensive purchase of entire lots was needed and the lots had to all be in a row. Usually the "L" selected lots at the quarter points so that if the next subdivision was oriented at right angles, the "L" easily slid across the boundary already positioned next to the alley.
The first "L", the South Side broke ground next to the alley at 25th St., just east of State St. The right of way for the most part was strung out on the west side of the alley, except in between 14th and 12th Sts. where the line crossed to the east side of the alley. The South Side was stymied trying to purchase needed land north of 12th St. The property owners did however agree to sign consents for the "L" to build over Victoria, an alleyway with a name, known today as Holden Ct., so the city agreed to modify the charter.
Although the franchise stipulated that 39th St. was the end terminal, before the tracks reached that point the Jackson Park Worlds Fair site was selected as the new end point. 39th St. was the city limits when the original charter was granted, but the new city limits had leaped to 138th St. in one fell swoop. The South Side chose the alley east of Prairie Ave. probably because the alley east of State was built up almost all the way to 63rd whereas the Prairie alley was mostly vacant . Plus to go behind State St. would encounter two large cable car buildings.
The "L" crosses from the west side to the east side of the alley in the 4800 south block. My thinking is they did that to avoid jogs to match up with shifts in the alley locations south from that point. Between 51st St. and 56th St., there is no alley. The east orientation also made the 61st St. yard a simple fit. Only one jog was needed to match a shift in the alley....at 57th and 58th Sts. A half block center track just north of the only island platform was put in at 58th St. Approved branches south to 71st and west into Englewood would have to wait, the first goal was getting the line to Jackson Park and the charter specified building through the blocks anywhere between 60th St. and 67th St. The South Side discovered building over 63rd St. to be a bargain....there was little development west of Woodlawn Ave. except for the thoroughbred race track. Property owners easily gave their consent, and the city agreed allowing the "L" to build a three track structure that included the spidery steel work over the raised embankment of the Illinois Central railroad. The entire extension from 40th St. to Jackson Park was built in under ten months. The east-west alignment alongside the Chicago Junction railroad would easily connect with two future extensions: to Kenwood and to the Stockyards.
The exception to the "build through the blocks" was the politically connected Lake Street Elevated. The charter specified "build along and upon" and the elevated was constructed using the street as a right of way and no signatures were ever solicited. But neither the city nor the railroad was bold enough to build east of Market St. so proper signatures were gathered and the over the street elevated won a charter east as far as Wabash Ave. Along most of Lake St., the cross beams were wide enough to allow an express third track to be added. When the street is your right of way, there is not much that can intervene in planning your route. Had the Lake Street built any of its chartered branches, they would have been built on private land conforming to a "build through the blocks" clause.
The third company on the scene put together the largest operation to date, a main line and three branches and all of it was built on private land. The Metropolitan West Side even brought their four track mainline to the edge of the Loop. The Met's four track main was constrained by Jackson and Congress east of Halsted; Van Buren and Harrison from Halsted to Sacramento Blvd.; and Adams and Polk from the boulevard west to the city limits.
Because of the extra number of blocks in the sections of land between Madison and 12th Sts. going west of State to the city limits, the blocks were more square than the typical rectangular city blocks with some lots having depths so deep that the "L" modified the customary "back of the lot right of way" and went through backyards with the garages on one side and the houses on the other. I would love to see photographs of those "L" structures. The Congress Superhighway obliterated all traces. The extra wide blocks gave the Met room enough to put their shop building and powerhouse in between the two pairs of the four track main.
The four track main ended at Marshfield station, a half block west of Ashland AV and branches broke off in two directions: the Douglas Park directly south and the Logan Square directly north. The Garfield Park, now only a two track main continued straight to the west. But at Sacramento the two track main shifted its east-west alignment two blocks to the south for reasons I haven't found yet.
Both the Douglas Pk. and the Logan Square branches to the south and north were located in the typical back of the lot, along-side the alley, right of ways, along with 1/4 block land purchases when the alleys ran perpendicular. Several railroad crossings utilized masonry and concrete structures beneath the iron "L" structure and the branches crossed already raised steam railroad with majestic truss bridges. On the Douglas branch was an exception: where it went over the Burlington railroad on a tight acute angle crossing that simply used extra long reinforced bent beams in a design so strong it was left unchanged in the Douglas rehab a few years ago.
The north-south alignment of the Logan Square branch is almost all gone north of the overhead crossing of the Lake Street elevated near Paulina. I say almost because the 1894 era bridge that carried the "L" over the C&NW railroad tracks still stands today because the railroad has signals mounted on the structure. Not only is it the oldest surviving "L" truss bridge, it or the South Side Jackson Park east 63rd truss bridge was probably the longest ever built in the city. When the Logan Square reached the diagonal Milwaukee Ave., the "L" followed a course parallel to Milwaukee, alongside the alley, a routing distinguished by a speed reducing kink at North Ave. where the "L" adjusted to property lines. Just beyond this kink the now demolished Humbolt Park branch went west, again, alongside an alley but it never reached its franchised end point of the city limits.
The fourth company had the least restrictive charter. The Northwestern Elevated could start at Monroe, in between Wabash on the east and Market on the west and build north, cross or tunnel beneath the river and then build anywhere east of the North Branch of the River and west of Cass (Wabash Ave.); it could build and build, until they reached the city limits. Just do it all on private land. The Northwestern laid out a four track main line, featuring express and local tracks patterned after New York City. The entire structure used tower bents, which by 1900 had become the standard engineering style. But making room for the Northwestern's four track elevated at the rear of lots left little room for buildings on the remainder of the lot. From the end point at Wilson Ave. they paralleled the Milwaukee steam railroad south to Graceland (Irving Park). From Graceland to Willow, the structure basically follows the alley east of Sheffield. But the almost three mile stretch has more kinks, shifts, jogs, than anywhere else on the city's "L" especially north of Diversey because the tracks constantly adjust to the alley location, constantly adjust to varied property lines when the alleys are perpendicular, plus, throw in lot lines aligned to the diagonal Clark St. near Roscoe. And not to be overlooked, are other highlights like the curves near North Ave. and Halsted St., long rumored to be caused by property owners who demanded too much money and the "church curves" where the Northwestern swung its right of way around St. Joseph's Church, just south of Division. Uniquely, both of the east-west alignments corresponded to proposed branches never built, but the proposed branch leaving the main at Graceland finally appeared as the Ravenswood leaving the main at Roscoe. The east-west tracks south of North Ave. are mid-block to align with a short street.
But getting to the Loop over private property proved impossible and the Northwestern petitioned property owners for permission to use streets. With consents in hand, the elevated received new franchises allowing an "L" structure over N. Franklin and N. Wells continuing onto Fifth Ave. (Wells Ave.), but only allowing two tracks which would continue to be a bottleneck down through history.
The four sided Loop was completely constructed over streets, sometimes after bitter fights for consent from property owners. The last Van Buren side was built using a ruse of chartering a mile long elevated from Halsted east to Wabash, but only building between Market and Wabash. It was easier to get consent signatures from industrial frontage owners in the west half of the mile than from the residential, commercial and retail owners in the east half. A simple majority, 51 percent approval from all the property footage along the entire mile as a whole was all that was needed. Perhaps to validate this ruse, the downtown "L" was numbered using the "proposed" Van Buren elevated as the origin. When the numbering got to Lake & Wells, Tower 18 was named. The downtown elevateds used a lattice design for stringers to let in more light at street level while opponents with the strongest objections held out for curb line upright supports along Van Buren and along Franklin. When the Northwestern opened in 1900, this early stage of the Chicago "L" system still had much expansion ahead. (to be continued)
David Harrison