Digital Plarail (ミニミニプラレール) was a series of computer-simulated Plarail (and Tomica) building games released by Tomy for Windows 3.1, 95, and later NT in the later 1990s and sold into the early 2000s. The base games includes only a few trains (the 100 series Shinkansen, 300 series Nozomi, and EF-65-hauled Blue Train), and shortly afterwards train packs began to be released.
The trains appear like 3D models, and the train packs include encyclopedia viewers that include facts about the trains and a way to rotate them around, but I get the impression that Tomy made these models and then rendered them out at the required angles to turn in a circle on the spot and saved them as static images, and then just displays the appropriate frame either when driving around or viewing the encyclopedias. These packs all retailed for 2000 yen originally.
The first train pack for the Digital Plarail system was the Train Pack 01 Shinkansen Edition (新幹線編 車両セット01). The title for the disk is PLARAIL3, suggesting it is the third release. The finalized files on the disc date to early August 1996, so it was probably released in later 1996.
These earlier expansions come in slim flip-open cardboard sleeves, with the disc coming in a mesh CD bag.
This pack includes versions of the Plarail 400 series Tsubasa, the first All 2-Story Shinkansen MAX, the sharknose Tohoku Joetsu 200 series, the WIN350, and the E2 Hokuriku Shinkansen.
In addition to adding these trains to the available selection, the Plarail Encyclopedia 1 and 2 applications that have descriptions for the trains in the base game and first pack is included. Installing this expansion upgrades the game to version 1.20.
Here is a scan of the disc. It has a neat wireframe of the 200 series Shinkansen that was probably rendered from the same model that made the in-game ones.
The first train pack for the Digital Plarail system was the Train Pack 02 Limited Express Edition (特急編 車両セット02). The title for the disk is PLARAIL5, putting its release after the first Special Scenery Set. The finalized files on the disc date to January 1997, so it was probably released in early 1997.
Like the first train pack, this release comes in the earlier style of flip-open packaging. This pack includes versions of the Plarail Boso View Express, Super View Dancer, L Limited Express, Sonic 883, and Narita Express.
Plarail Encyclopedia volume 3 is included to give some information about the trains in the pack, and volume 1 is installed if you don't already have it from the first train pack.
Digital Plarail Train Pack 02 disc, with the Sonic 883 series wireframe.
The final regular train pack for the Digital Plarail system was the Digital Plarail Vehicle Set 03 Cargo Edition (貨物編車両セット03). The title for the disk is PLARAIL9, placing it after the first Thomas and Friends pack. The finalized files on the disc date to September 1997.
The pack includes nicely-liveried versions of the EF-81, EF-58 in brown, EF-66 in freight livery, and DD-51 as well as six freight cars, the mail car and livestock car, a container car,a yellow tank car and blue car transporter like included with the D-51 Locomotive with Light, and the classic guard's van.
The pack installs Plarail Encyclopedia 1 and 4 and updated the game to version 2.0 Actually, the text for Plarail in the encyclopedia files changed slightly for this release, so it installs a new version of encyclopedia 1.
The disc for Digital Plarail train pack 3, with the DD51 wireframe on it.
Around 1999 Tomy began selling downloads for individual trains from the Digital Plarail train packs on their website. It does not seem any exclusive trains were distributed this way, but the 500 series Shinkansen included in the DX pack as well as the 400 series Tsubasa, E2 Hokuriku Shinkansen, the DD51 locomotive, and the Shinkansen MAX were sold individually for 400 yen.