Loomis Junction
Loomis Street and the Eisenhower Expressway, Near West Side

Service Notes:


Blue Line: Forest Park

Quick Facts:

Established: June 22, 1958
Original Line: West-Northwest Route, Congress-Douglas branches
Rebuilt: n/a
Status: In Use



Loomis Junction was established on June 22, 1958 when the Douglas branch was rerouted to join the new Congress Line. The elevated Douglas branch connected to the expressway median Congress Line by way of a long ramp descending into the depressed median, connecting at a junction located at Loomis Street, immediately west of Racine station.

Loomis Junction was automated from the outset. The automated routings were initially accomplished by means of a device called a Train Identification Coil or "Identra-Coil" (sometimes nicknamed "the toilet seat" because of its shape). This was an electronic device, first used at Paulina Junction four years earlier, carried by the lead car of each West-Northwest Route The coil for Milwaukee-Congress trains was identified by a red stripe painted on the tuning coil box and operated at a frequency of 92 kilocycles. The Milwaukee-Douglas coils had a green stripe and operated at 100 kilocycles.

The motorman obtained the coil before the beginning of his run from the terminal clerk when going on duty and returned it when going off-duty (unless directly relieved by a motorman requiring use of the coil). The motorman inserted the coil in a bracket mounted on the right front of the train. (On the 6000-series trains, the middle safety spring had to be hooked over the bottom one to avoid damaging the coil.) Coils could not be placed between coupled cars due to possible damage to the coil and failure to transmit.

As a train approached the junction, an electronic device (e.g. the coil) passed in front of a trackside electronic receiver device which automatically set the proper switches for the train. Automatic selection for eastbound trains was on a first come, first served basis. If the correct route failed to be automatically set by the transmitter, the motorman could manually set the route by operating levers on the wayside route selector.

The Identra-Coils were used for 20 years until May 1978, when a new interlocking plant was placed in service at Loomis Junction. The new interlocking still routed eastbound trains on a first come, first served basis. Westbound trains were now simply routed in an A-B-A-B sequence -- one Congress train, one Douglas train, one Congress train, and so on -- as the service was scheduled such that trains for each branch were evenly scheduled on an alternating basis. The new interlocking plant eliminated the use of Train Identification Coils on trains. Route selectors were still available westbound if an incorrect route was established by the interlocking plant.

The automated, alternating-sequence interlocking was used for almost 30 years until Douglas branch service was revised. Effective Sunday, June 25, 2006, the majority of Douglas trains used a new Pink Line routing, sending them to the Loop via the Paulina Connector and Lake branch rather than to O'Hare via the Congress Line. This meant that Blue Line service now primarily consisted of O'Hare-Forest Park service. There were, however, still some O'Hare-54th rush hour trains that still needed to access the Douglas branch through Loomis Junction. As such, the automatic interlocking logic at Loomis Junction was modified to route all southbound (i.e. westbound) trains to the Forest Park (Congress) branch. Blue Line trains operating from O'Hare to 54th/Cermak must use the wayside route selector to establish the proper lineup at Loomis Junction. In order to help reduce waiting time for the interlocking to establish the desired lineup, a new route selector was installed at Racine station at the 8-car berth marker. This selector duplicates the one located near the west end of the platform.

After a two-year experimental period, the CTA revised service on the Cermak branch to eliminate the rush period Blue Line trains, leaving the Pink Line to provide all service to 54th/Cermak. The last day of Blue Line Cermak service was Friday, April 25, 2008. Today, Loomis Junction is operated on automatic, with all revenue trains moving through the interlocking on the "main line" routing. Only nonrevenue trains use the diverging route to access the Pink Line.



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