Plarail 3-way Automatic Point Rail

In light of recent discussion in another place, I've just put together this little item.

The original 3-way Automatic Point Rail has been around since 1978, when it was released in its own Automatic Point Set along with the 583 series Sleeper Limited Express.

  

The first catalogue illustration I can find showing it as an individual item is from 1981. You can see the distinct hump-back configuration.

It's possibly more familiar to those of us in Europe and the Americas in its 1987 dark blue Tomy Trains form, which had a differently shaped sliding actuator to match the different configuration of the Tomy Train engines, and which had the auto/manual slide knob labelled in English.

At some stage there was a modification of the old humped J-16 which involved the shape of the slot in which the actuator slides from the simple shape of the first release to the shape required by the Tomy Train actuator. I'm speculating that this change wasn't made to accommodate any change in the Plarail actuator, it must just have been made so that the Tomy Train and Plarail versions used a common mould, and for that reason would have been about 1987. At the same time the notation beside the auto/manual slide knob was changed from Japanese to English.

In 1992 when numbering of rail and scene parts was introduced, it became R-16.

At some point between then and now, the configuration of R-16 changed from the hump-backed form to the current flat form. At the same time the slot reverted to a simpler shape and the flanges beneath the male and female connectors were removed.

 

There are also some minor differences in the internal mechanism:

 

Finding the date of introduction of the new flat form is made more difficult because online retailers continue to use images of the first old one with the original slot right up to the present day. The first Plarail catalogue to illustrate R-16 with a picture of the new one is the 2012-13 edition.