In 1975 during the last era of liftoff box tops the Chikatetsu Silver Train was released with a fresh tooling that seems to have been an early adopter of the milky white plastic gearbox. The following year the "Subway Train" (地下鉄電車) was released in the "train" box style. The Subway Train is silver (in most iterations, silver-plated plastic) with green accenting, with a wraparound green sticker adding the head and tail lights to the end cars. Another sticker fills in the front and rear windows, with later versions explicitly depicting a subway train on the Chiyoda Line on the Tokyo Metro. The molding of the train itself resembles the Eidan 6000 series trains which entered service in 1971.
In 1976 the three-car train release Subway Train was introduced in the fourth-generation "train" boxes. Other than the boxes, these earlier releases all would have used the older more fragile style of axle holders, which most likely also appeared in the first few years of the fifth generation release shown below before the tooling was updated by the early 1980s.
In 1978 the Subway Train was rereleased in fifth generation EC boxes as EC-06 Subway Train (地下鉄電車). These releases are very similar and feature the driver in the cab at both ends.
The silver plating on these trains wears away with play and storage and battery acid eats it away until the plastic turns yellow or even translucent... Almost all of these trains have some scratches or small patches at best.
I have a complete three-car train from some time in the 1980s that uses the more modern chassis style but I also have the intermediate and tail car (actually, two tail cars) from older Subway Trains with the fragile axle holders. Based on the consistently-yellowed rear couplings, it is likely they date to 1978 or 1979.
A nice four-car old power train...
In 1987 the first new power Subway Train was rereleased with the green stripe carried all the way down the car bodies. The front window sticker does not have a driver, just some window glare. The text above the window reads 代々木上原01S, referring to Yoyogi-Uehara Station in Tokyo.
The plating on these trains seems like it was a little shinier than the old power ones to begin with and this one had actually has survived pretty nicely... the chassis for these Japan-made new power Subway Trains is based on the mid 1980s radio control version, with the remnant cutouts in the intermediate car chassis from where the control electronics clipped in and the clip that held the antennae wire in the chassis of the tail car.
This example was produced in April 1992, when Japanese-production single-speed trains had switched to using white power switches. This is perhaps the nicest release of the subway train with direct-drive power, but you do miss out on the driver in the window...
In 1994 with the introduction of seventh generation boxes the Subway Train was rereleased for the last time, now produced in Thailand. These late Subway Trains do not have the silver plating applied and are just a silvery-grey plastic which is not nearly as flashy as their earlier counterparts but I still do enjoy the look of it.
My seventh generation Subway Train was produced in May 1997 and is in okay condition with some worse-for-wear stickers. It is fairly clear that this is an older tooling, with different construction methods for the intermediate and tail cars as well as a somewhat odd (although I must say, rather interesting looking - I like the way the rear of the chassis hangs low and covers more of the powered rear wheels) power car chassis that was updated for the new power gearbox with the 1987 rerelease. The toolings are descended from the retooled radio control chassis used for Japanese new power production previously. The pantograph on all these releases is simply clipped into place.
This style of subway train was discontinued when the range was revamped around 2003. During the 1990s the amount of different commuter subway lines that Plarail offered toys of expanded dramatically and with the modernization of the range the relatively old Subway Train was not kept around. In fact, it seems at some point during this iteration's lifespan a Plarail sticker book contained stickers to cover the headlights and green stripes on the Subway Train into yellow or orange to represent the Hanzomon and Yurakucho lines - I found this blog post (archived) showing these stickers as well as additional modifications to make the 6000 series look more like an 8000 series train. I do think it is cool that Tomy kept the train in the range for as long as they did, even though it was showing its age by the time of its last rerelease. The real 6000 series trains actually outlasted the Plarail train by more than a decade, staying in regular use until spring 2017 on some lines. The original 6000 series prototype car is apparently still used for training operations, and some trains were still in use in Indonesia at least as recently as 2020.