The CTA's next generation of rail cars will include a mix of forward-facing and aisle-facing seats, a pretty quick departure from the unpopular aisle-facing seats on the 5000 series. The $1.3 billion project, approved in March, will replace half of the CTA's train fleet with newer 7000 series cars to be built over 10 years. The first cars will hit the rails in 2019.

Since wooden train cars of the early 1890s, about a dozen different series of cars have traveled on the "L," a 130-year evolution in the experiences of commuters. Here are highlights.

Wooden rolling stock Specifications Seats: 46

46 Length: 46 feet

46 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet, 6 inches

12 feet, 6 inches Builder: Jackson & Sharp About These wooden cars were pulled by steam locomotives and featured doors on either end of the car. Interiors were luxurious with varnished wood, ornate lighting, slatted window shades, cork floor mats and rattan seats. Originally, the cars were heated by steam from the locomotives and were lit by gas lights supplied from tanks under the floor. 4000 series Specifications Seats: 52

52 Length: 48 feet, 6 inches

48 feet, 6 inches Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet, 3 inches

12 feet, 3 inches Builder: Cincinnati Car Co. About The first steel body cars had wide pneumatic sliding doors at each end of the car. The more advanced "plushies," built in the early 1920s featured plush seats, circulating fans and porcelain enamel handles to hold on. 5000 series Specifications Seats: 96

96 Length: 88 feet, 7 inches

88 feet, 7 inches Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet, 2 inches

12 feet, 2 inches Builder: Pullman Car Co., St. Louis Car Co. About Three passenger compartments were mounted on four sets of wheels. Passengers could move between through end doors. 6000 series Specifications Seats: 47-51

47-51 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 11 feet, 10 inches

11 feet, 10 inches Builder: St. Louis Car Co. About These cars were the CTA's guinea pigs, used for all sorts of trials involving lights, signs and window types throughout the 1960s and '70s. These were the first cars to experiment with air conditioning in 1958. 2000 series Specifications Seats: 47-52

47-52 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: Pullman Car Co. About Innovations included fluorescent lights, picture windows, air conditioning and remote-controlled destination signs. 2200 series Specifications Seats: 47-51

47-51 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: Budd Company About First cars with the current stainless steel look. Features included large windows and roof-mounted air conditioning. A 1990 rehab replaced the padded seats with fiberglass seat frames with inserts. An openable window on top of the standard window was also added. 2400 series Specifications Seats: 45-49

45-49 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: Boeing-Vertol About The first cars in more than 50 years to have sliding doors. 2600 series Specifications Seats: 43-49

43-49 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: Budd Company/Transit America About The 2600s' interior space is slightly larger than the 2400. The seating arrangement is unchanged except for the addition of a single wheelchair-friendly fold-up seat behind the cab. Increased use of fiberglass insulation reduces noise levels. 3200 series Specifications Seats: 39

39 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: Morrison-Knudsen About After a brief hiatus, the design again included hopper windows. These are the first cars to adopt LED destination signs. As ridership increases, seating is sacrificed to make more standing room. A few of the cars had all seats removed and were labeled "MAX." The trial proves unpopular with riders and causes weight distribution problems on the train. 5000 series Specifications Seats: 38

38 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: Bombardier Transit Corporation About These cars featured the unpopular aisle-facing seating. New features also include LED lights inside and out, seven interior security cameras, onboard event recorder (i.e. black box), interior system maps with location indicator lights, chimes when the doors opened and glow-in-the-dark floor markings. 7000 series Specifications Seats: TBD, at least 38

TBD, at least 38 Length: 48 feet

48 feet Width: 8 feet, 8 inches

8 feet, 8 inches Height: 12 feet

12 feet Builder: CSR Sifang America JV About The exterior and interior design of these cars is yet to be determined. Early renderings show seating will consist of a mix of aisle- and side-facing seats.