chicagopcclcar Posted November 1, 2012 Report Share Posted November 1, 2012 2013 will have some interesting reroutes on Chicago's 'L'/subway system. We already have the planned five month shutdown of the Red Line Dan Ryan with Red line trains rerouted over the Green line from 17th Street tower to Ashland/63. Now two nine-day reroutes of the Brown and Purple lines has been announced for completion of a year-long replacement project by the City of the Wells Street bridge over the Chicago River slated for "early" March and "late" April. It must be pointed out, though, no mention of the Purple line has been contained in the publically released statements. Running some Brown line trains through the State St. subway is historically note-worthy as this would duplicate in part the original routings when the subway opened back in 1943. The Ravenswood route was paired with the Englewood/Normal Park and the Howard route was paired with the Jackson Park with some trains going all the way into Evanston. For the latter service, Jackson Park trains always had the trolley equipped 4000s cars. This lasted until 1949 when the CTA revised the subway service and made the Ravenswood and the Evanston routes separate services entirely. Two important operations are unmentioned in all the press releases and news coverage: what will happen to Purple line service on the weekday closures and where will the north side trains be turned from south to north. So called "middle tracks" are ideal turning locations as they allow the turning train to quickly get out of the way of normal traffic and change ends for operation, again out of the way. Going back into service in the reverse direction is coordinated with Rail Control. The entire operation can be assisted by a towerman or it can be handled entirely by the train operator of the turning train. Middle tracks are located on all three lines accessible from the State St. subway; the Green, the Red, and the Orange. David Harrison https://www.cityofch...ertobeginm.html 1 Quote Link to comment Share on other sites More sharing options...
Fails the Turing Test Posted November 2, 2012 Report Share Posted November 2, 2012 It's interesting that they're going to send Brown (and maybe Purple?) trains through the subway for this. What are the turning options available? If they close the Dan Ryan beforehand, they might use the interlocking south of Roosevelt to turn trains. If they don't, can they use the 13th incline to turn trains? I seem to recall that Ed Zotti reported it wasn't, for technical reasons (because of the incline), in a column suggesting sending the Purple through the subway as a matter of course. The next option is south of 35th-Bronzeville-IIT, which seems an awfully long way to go to turn a train. Quote Link to comment Share on other sites More sharing options...
chicagopcclcar Posted November 2, 2012 Author Report Share Posted November 2, 2012 It's interesting that they're going to send Brown (and maybe Purple?) trains through the subway for this. What are the turning options available? If they close the Dan Ryan beforehand, they might use the interlocking south of Roosevelt to turn trains. If they don't, can they use the 13th incline to turn trains? I seem to recall that Ed Zotti reported it wasn't, for technical reasons (because of the incline), in a column suggesting sending the Purple through the subway as a matter of course. The next option is south of 35th-Bronzeville-IIT, which seems an awfully long way to go to turn a train. The turning options are what is known as middle tracks..... they allow the turning train to quickly get out of the way of normal traffic and change ends for operation, again out of the way. Going back into service in the reverse direction is coordinated with Rail Control. The entire operation can be assisted by a towerman or it can be handled entirely by the train operator of the turning train. Middle tracks are located on all three lines accessible from the State St. subway; the Green, the Red, and the Orange. It is true that the middle tracks are not located close to Roosevelt station (Red line), but travel time for the two weeks is not that excessive. The south side incline can't be used because it isn't connected to both main tracks. The Red line shutdown and the Wells Street bridge work do not occur at the same time, so the Red line would not be shutdown and rerouted while the bridge work is going on. D. H. Quote Link to comment Share on other sites More sharing options...
BusHunter Posted November 2, 2012 Report Share Posted November 2, 2012 With the Brown line having frequent service and the Red line having frequent service, (both can have service 3 to 5 minutes apart at their peak) it may just be impossible to run all those trains through the State st. subway without major gridlock. I wouldn't want to even think about the turning of all those trains at Roosevelt. If they did run those through the State st. subway it would just make more sense to send those trains to Midway, but there would be delays. The Purple line could always be cut back at Howard for 9 days or they could just run those to Merchandise Mart. This way they wouldn't lose the near north side elevated ridership. Maybe they could run a shuttle train or turn every other Brown line train back at Belmont. There's lots of possibilities. Quote Link to comment Share on other sites More sharing options...
chicagopcclcar Posted November 2, 2012 Author Report Share Posted November 2, 2012 With the Brown line having frequent service and the Red line having frequent service, (both can have service 3 to 5 minutes apart at their peak) it may just be impossible to run all those trains through the State st. subway without major gridlock. I wouldn't want to even think about the turning of all those trains at Roosevelt. If they did run those through the State st. subway it would just make more sense to send those trains to Midway, but there would be delays. The Purple line could always be cut back at Howard for 9 days or they could just run those to Merchandise Mart. This way they wouldn't lose the near north side elevated ridership. Maybe they could run a shuttle train or turn every other Brown line train back at Belmont. There's lots of possibilities. The CTA news release states only half of the Brown line trains will be rerouted to the State Street subway. The other half will terminate on the elevated at Merchandise Mart. The Purple line is not mentioned. DH Quote Link to comment Share on other sites More sharing options...
BusHunter Posted November 2, 2012 Report Share Posted November 2, 2012 The Purple line is not mentioned. Probably because that's the bad news. There's probably going to be no service for the Purple line there. Quote Link to comment Share on other sites More sharing options...
chicagopcclcar Posted November 2, 2012 Author Report Share Posted November 2, 2012 Probably because that's the bad news. There's probably going to be no service for the Purple line there. The true "unknown" is what is the actual capacity of the State Street subway. When it opened in 1943, it could handle a train evey 90 seconds. This was with complete wayside block signal protection. Top train speed was about 40 MPH, all with air brakes. Over the decades, the trains got faster, today's top speed is 55 MPH, but no more air brakes, LOL. The signalling was replaced with cab signals. With higher top speeds, the safety distances expanded. How the expanded safety margins affected the number of trains per hour is not known, except by the CTA planners. The latest signal addition are what I would call wayside closing signals that allow following trains to close in at a slow speed behind trains berthed in stations. The closing feature was included in the original block signal system. The questions to be answered are: do the closing signals increase capacity of the subway; does a slower top speed also increase capacity. Obviously CTA planners DO HAVE this information and they can plan increases in service with a predictable level of success. DH Quote Link to comment Share on other sites More sharing options...
mkohut Posted November 4, 2012 Report Share Posted November 4, 2012 Here my question.The 500,000 they claim they are going to save. What is that money going to be use for. Quote Link to comment Share on other sites More sharing options...
Busjack Posted November 4, 2012 Report Share Posted November 4, 2012 Here my question.The 500,000 they claim they are going to save. What is that money going to be use for. For a press conference saying that they might fix something else. That is, even if it exists. Quote Link to comment Share on other sites More sharing options...
chicagopcclcar Posted November 17, 2012 Author Report Share Posted November 17, 2012 The true "unknown" is what is the actual capacity of the State Street subway. When it opened in 1943, it could handle a train evey 90 seconds. This was with complete wayside block signal protection. Top train speed was about 40 MPH, all with air brakes. Over the decades, the trains got faster, today's top speed is 55 MPH, but no more air brakes, LOL. The signalling was replaced with cab signals. With higher top speeds, the safety distances expanded. How the expanded safety margins affected the number of trains per hour is not known, except by the CTA planners. The latest signal addition are what I would call wayside closing signals that allow following trains to close in at a slow speed behind trains berthed in stations. The closing feature was included in the original block signal system. The questions to be answered are: do the closing signals increase capacity of the subway; does a slower top speed also increase capacity. Obviously CTA planners DO HAVE this information and they can plan increases in service with a predictable level of success. DH Someone asked me to explain "closing signals." Wayside block signals are spaced so many hundreds of feet apart. Approaching stations, the spacing is shortened such that you might have four signals and blocks where out on the main there might be only two. This is the closing zone and I remember seeing the typical large black letter "T" on a yellow background on visiting both the New York subway and Toronto's subway. With the leading train berthed in a station, if the following train has stopped or is moving slowly enough, the red signal will clear to yellow and the train can approach the next signal. All of the signals in the closing zone will similarly clear, one by one, except the last signal that protects the leader train stopped in the station. DH Quote Link to comment Share on other sites More sharing options...
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