Cars of railway vehicles often differ. Even in the same model, detailed specifications such as coloring design of bodies or the type of equipment are subtly different in each car. Finding such small differences is one of the great pleasures for rail fans like me.
The EMU Toei 10-300 series is a visible example. This model was launched in 2005 replacing the old 10-000 series. Currently, there are three types of the 10-300 series. Let's look at the differences of these three types of trains focusing on the front car designs.
Group A is the 1st and 2nd batches of the 10-300 series. It has two centralized frontal lights on the top part of its "face". A thick light green colored and a thin dark blue colored stripes are seen on the body.
Group B is the 3rd and 4th batches of the 10-300 series. It has two separate frontal lights on the lower part of its "face". Thick green and dark blue colored stripes are seen on the face, but a blue colored stripe is thin on the side body.
Group C is the 10-300"R" series. It is almost the same as that of Group A, but the light green colored stripe on the side stripe is thinner than that of Group A. The dark blue colored stripe on the side body is shorter than that of Group A.
Is it complicated? Non-rail fans probably cannot understand this strong preference.
More information about the EMUs on the Toei lines (in Japanese):