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Metal Architecture
Monday | 24 August, 2015 | 1:32 pm

Reviving Chicago's railway

By Gretchen Salois

The bloodline of a pulsating metropolis, efforts to restore Chicago’s aging elevated train structure go beyond mere maintenance

August 2015 - Each weekday as the sun peeks over Lake Michigan, Chicagoans awaken to another commute. Hoards of riders crowd the platforms of Chicago Transit Authority’s elevated train, or the ‘L,’ that circulates about the city. Efforts to retain the integrity of platforms and stations built during a bygone era combine functionality and safety without sacrificing charm and character. It is easy to overlook the painstaking craftsmanship throughout these stations while navigating rush hour—but to stop and look may be worth losing your spot on the incoming train.

Horse-drawn public car service launched in Chicago in 1859. The city introduced cable cars in 1882, followed by electric streetcars in 1890. The first rail line appeared in 1892, and since Chicago’s unique elevated train opened in the downtown “Loop” in 1897, steady advancements led to today’s modern transit system. 

The CTA’s infrastructure is in constant use so maintenance isn’t as simple as shutting down to make repairs. With constant wear and tear comes inevitable deterioration. Routine maintenance keeps the trains on track but as some stations have withstood more than a century of use, modernizing can prove rather challenging. 

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No guesswork

Reusing materials original to the station and recreating pieces where re-fabrication is not possible requires seriously thoughtful work. “If you have to replace station components because the old parts are too fragile to fix, let’s at least be really accurate with how we replicate those pieces,” says Preservation Chicago Executive Director Ward Miller. 

Preparation for the station restorations at both Damen Avenue and California Avenue depended upon a high level of coordination among numerous parties, especially as each project was to be completed in a tight three months, accomplished by working 24 hours a day. 

As described by CTA’s architectural historian, Marlise Fratinardo, the restoration involved the Illinois Historic Preservation Agency, the City of Chicago, local aldermen, a contracted design team and the CTA to ensure the project met the standards of safety and conservation. “We approached the project with a detailed assessment of existing conditions and materials,” Fratinardo says. “It took a lot of collaboration to develop sensitive upgrades that also met contemporary needs.” Fratinardo and Ross Barney Architects coordinated the project.

Using original drawings from the 1895 Damen station construction, Fratinardo says the team prioritized the exterior for preservation treatment. “The station already fits seamlessly with the surrounding commercial buildings,” Fratinardo says. “We wanted to enhance its existing historic features. So we removed various items, such as contemporary lights that were added in recent decades and did not convey the 1890s period.” For example, compatible LED light fixtures were used on poles that referenced the original design.

To put the project in perspective, “when these stations were built in the 1890s, public transportation options consisted primarily of horse-drawn cars and cable cars,” Fratinardo says. “The introduction of an elevated rail system brought new technologies to Chicago’s neighborhoods and featured stations that were highly innovative for their time.”  

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The Talladega touch

Senior Project Manager Matt Moss—of F.H. Paschen, S.N. Nielsen in Chicago—headed the bidding process to take on the project. After the successful bid, Moss says the general contractor believed Talladega, Alabama-based Allen Architectural Metals Inc. was a natural fit. The experienced restoration and fabrication company has worked with F.H. Paschen before and is an expert with cast iron, which is what was used for the railing posts and historic light poles at the Damen station. “We had a 63-day period to rebuild and refurbish the Damen station and platform,” Moss recalls. 

As workers embarked on the project, they realized just how much time and effort was invested during the original construction. “When Allen started stripping paint off these old cast iron posts, we noticed that each was individually numbered,” Moss recalls. “That was very interesting because in the high production world we live in, it’s not something that’s done. There was a lot of time and craftsmanship invested in these pieces over a century ago—a very different scenario from today’s construction techniques.

“The goal was to bring as many of the elements from the original station back which, over the course of the years, had been lost due to repairs or replacement of original construction.”

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Attention to detail

Clinton Ramey, project/procurement manager at Allen Architectural Metals, worked on the actual fabrication of parts restored or repaired from the Damen and California stations, restoring and re-creating hand railings, ornamental cast iron support posts, ornamental cast iron light posts and all historical stairwell railing components made from A36, cast iron, bonding cast iron and A36 hot-rolled mild carbon steel.

After stripping all components of any lead paint—a challenge in itself—time was another hurdle the fabricators faced. Oxidation begins the moment the paint is stripped, exposing the original metal. “A lot of times when you leave the older lead paint on the railings or posts, it will hide other issues or needed repairs,” explains Ramey. “This allowed us to look at each post and panel to form our own opinion on what repairs or replacement parts were needed.”

The handrail panels each presented different issues and the amount of planning involved house surveys, photos of each component, and documenting each panel before any fabrication work began. “The plan of attack in our business can make or break you,” Ramey says. “Though plans can change, proper planning can save much time and headaches that can arise during historical restoration.” On these particular railings for the Blue Line, fabricators started at the cap rail and worked their way down to the bottom angle to make sure all problems were addressed.

The cap rails were made from square tubing, round tubing, square tubing with C channel, flat bar and flat bar with C channel. “The most critical damage to these railing panels were at the cap rail, thin-gauged panels within the railing and steel angle connection points meeting the cast iron posts,” Ramey says. 

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“For instance, the angle connection points were all different sizes for each railing. They even had dimensional differences from the top angle of the railing to the bottom angle of the railing,” he recalls. “This caused issues when procuring the material and also when fabrication began.”

Ornamental features like the diamond shapes styled into the panels were compromised and broken due to oxidation and harsh weathering. Those deteriorated by oxidation were completely replaced. “We used our waterjet machine to cut these panels to the size of the originals,” says Ramey.

Working with antique cast iron presents its own challenges, according to Ramey. “We had to repair the light post baseplates and repair cracks within the shaft of the post. When repairing cast iron, replacing broken or voided sections and anything involving structural integrity, steel is applied [with heat] to strengthen the area or component. In many situations this pre-heating technique is used to bond the steel replacement to the existing cast iron so there is a true bond between the two materials.”

A pre-heating technique was used to repair spider-web and deep cracks within the cast iron posts. Preheating before welding slows the cooling rate of the weld and the region surrounding the weld, explains Ramey. Using a low current to minimize admixture and residual stresses, it is sometimes necessary to restrict the welds to 1-inch-long segments to prevent buildup of residual stresses that can lead to cracking. “Wrapping the casting in an insulating blanket, or burying it in the dry sand will help slow cooling rates and reduce cracking tendencies,” Ramey says.

Applying strength

Allen Architectural Metals consulted an engineer to create a repair design that would integrate the tops and bottoms of each light post into a singular unit again. This required inserting a square steel tube the entire length of the post and fastening it in a uniform way to ensure the connection points between the original post and steel tube insert were strengthening the cast iron and not making it weaker. “We also welded solid the cracked portion of the light post after making it one unit,” says Ramey, which also smoothed out the surfaces. Fabricators also used reciprocating saws, cutoff wheels and hand torches to break free the original fasteners and welds that held these cap rails to the railing. 

Skilled fabricators, says Ramey, succeed in taking “a deteriorated cast iron façade, a broken-down historic railing system or even a new modern design, and either restoring or creating something that is completely unique and to the upmost ends of quality,” says Ramey. “I get to see exactly this in our fabrication shop daily—taking pride in your work can move mountains.”

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Pillars of steel

The upgrades to Chicago’s aging commuter train stations continues as the historic Quincy station on the Loop elevated line is in the works. In order to meet Americans with Disabilities Act guidelines, the rehabilitated structure will include an elevator.

“We’re making a list of what we can keep and what needs to be replaced—all while adding two new elevators which is very exciting, making the station accessible to everyone,” Fratinardo says. 

The Quincy station will offer a new set of challenges as it isn’t surrounded by brick but, rather, elevated above the streets on pillars of steel. 

“I remember a time when various agencies were discussing a plan to demolish the Loop elevated structure and redirect it into a subway system,” recalls Miller. “That plan was later shelved. I don’t think anybody could imagine downtown Chicago without the ‘L’ maneuvering through the city’s downtown urban core.” MM

GALLERY: Historic photos of CHicago's CTA

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