Minecart Rapid Transit system
The Minecart Rapid Transit system or MRT is a rapid transit system that uses minecarts to be transported around a Minecraft world, designed by Frumple. There is no size limit to an MRT network, as stations are completely independent of each other. In general, players use the stations by boarding minecarts in designated departure areas, and then remaining in the cart until arriving at the desired station at which the player can exit and return to the concourse. MRT stations are designed for two-way, multiplayer traffic.
The MRT has had several different iterations of the station. Each iteration brought new functionality from Minecraft updates into the game, and also making the stations more user-friendly and stable for multiplayer use.
Version 1.0 (Beta 1.1)
MRT v1 was the first version of the station. It was built back in the early days of Beta 1.1 and 1.2. This station used a vertical cart hopper to store its carts, and perpetual motion boosters were used to move carts around since there were no powered rails in this version of Minecraft. This station was not very compatible with SMP, as it had many bugs and relied on moving carts which could get stuck upon the unloading of a chunk. Because the station uses glitch boosters, it does not work in Minecraft Beta 1.6 or later. The station came in two flavors: a central platform and a side-platform station. The central platform station allowed for players to change direction on the same platform, without needing to go through an underground concourse like what must be done in the side-platform station to do the same.
To use the station, players stand on a pressure plate which calls a minecart from the cart hopper by allowing a perpetual motion cart booster to exit its loop and push a cart out of the bottom of the hopper. The booster returns to its loop while the cart arrives at the boarding area, where the player just needs to enter the cart to be launched and exit the station. Boosters guide carts along the long stretches of track between stations. To arrive, players must press a button on the right side (if arriving at a side platform station) or left side (if arriving at a center platform station) of the track just before entering, after which they will be redirected to the arrivals area. If a button is not pressed the cart continues on its merry way to the next station.
Once in the arrival zone, players simply need to exit their cart and it is automatically collected by the retrieval system. The arrival area has two lanes per direction, which close off while in use. If both are in use and a third player arrives, arrivals are denied and the player must skip the station or get off at the next one and turn around. There is also a turn-around switch at the exit of a station that can be used to reverse direction and access the arrival bay for the opposite side.
Version 2.0 (Beta 1.2)
MRT v2 was the second version of the station, and included minor improvements by Frumple. Changes in v2.0 included a revamped cart request system, moving it right next to the departure bay, and replacing the pressure plate with a button. Additionally, the station replaced the perpetual motion boosters with door boosters, making the station better equipped for SMP use. With the new door booster design the cart only moves when needed so the cart would not get stuck when the chunk was unloaded. Noteblocks were also added and played when a cart was called and when arriving at the station.
Also added was a way to deal with overflow carts when the dispenser was full. If the dispenser was full the cart would bounce back and get destroyed by a cactus. The concourse from the center platform variation was added to the side platform station. And finally Frumple created two "large, ominous, evil-looking, stone cubes of death" otherwise known as new underground variations of the station, which removed the windows and added paintings on the inside walls. All other aspects of the station remained unchanged from version 1.0.
Version 2.1 (Beta 1.3)
Version 2.1 of the station was a minor update to version 2.0. The first change in this update was instead of playing a chord when arriving at the station, the noteblocks played a chime, this was possible thanks to the redstone repeaters in the new update. Additionally, dispensers with minecarts in them were added above the extra minecarts chest near the hopper reload track. Frumple added into the arrival bays "assisted cart disembarking" as well. Players boarded a stationary cart when arriving at a station, to prevent the cart getting knocked out of place when the player was exiting. Also, due to a bug with pressure plates at the time that made it so the player could end up inside the cart hopper, Frumple added emergency exits to the hopper so the player would not have to break the glass to escape. Finally, Frumple added the ability to change wool colors on the station to color code lines, a feature used on the MRT server today. And also added were entrance schematics to attach to the overground variations of the station.
Version 3.0 (Beta 1.6)
Following the deprecation of glitch boosters, the MRT was upgraded in Beta 1.6.6 to v3.0, the oldest still-working station that used several new technologies (for its time).
v3.0 used a horizontal minecart dispenser capable of holding twelve carts per direction, and powered and detector rails to manage the dispenser as well as the arrival bays. Carts were requested with a button and would automatically depart after a short delay. v3 included a new flavor, Ground level, where the main level of the station had windows but the dispenser level, which was below the main, was underground.
This was the version put on the MRT server at first. An improved version of MRT v4.0, it had three booths and would not require glitching through a wall for exiting. However, the dispenser was known to have glitches with rails getting randomly deleted due to the stations being so large that they straddled several chunks, and the infamous "Dispenser'd" glitch where a player would have so much lag going through the station that they would get redirected into the dispenser of the station. An endangered species, most were updated to v4.2, although some, such as Robin's Hill, still remain as v4.1.
This version of the MRT station was a modification of v4.1 made by Frumple and Omricon, in which the dispenser system was replaced by a hopper system. This allowed the storage capacity to dramatically increase from a mere 26 carts to hundreds upon hundreds of carts. It was soon instituted on most MRT stations. However, the main side-effect was that it exacerbated the "Dispenser'd" glitch - because the cart would have to go into a chamber so it could go into a hopper when it enters the dispenser, if a player got dispenser'd they would get stuck in the chamber and have to respawn or relog to get out.
MRT v4.3 is one of the few MRT station versions that was not built by Frumple. It was built by thomasfyfe, a server administrator at the time. Thomasfyfe is also owner of Cyan Systems, a rail technology company, which is why parts of the v4.3 design have similarities to Cyan Systems stations.
The v4.3 station notably removed the old dispenser level entirely. Empty carts were discarded by having them fall into lava, and an infinite dispenser would replenish the carts. This removed the space requirement for the cart dispenser and reduced lag by reducing the number of active cart entities within the station. This station also replaced the fence/post cart detector used on previous MRT versions with a tripwire detector, which made it less susceptible to the cart detector glitch, whereby a player would end up in the dispenser level. In addition, should the cart detector glitch still happen, it was now easier to get out of the station's interior due to there being less of it
O19 station was the first station to test the v4.3 version; after this it was used to replace all the stations within Spawn City limits with the exception of Harbourfront District, which had not been annexed at the time. No plans to replace any of the other stations on the Old World MRT system have been made.
Version 5.0 was unveiled by Frumple as a Christmas gift for everyone. The lab can now be accessed at Spawn. The final version was used on the new world for the new MRT lines. Like v4.3, it used tripwire as a cart detector instead of a fence/post. In addition although the "Dispenser'd" glitch was not eliminated entirely, it was made to be easier to get out of since the cart wouldn't go into a small chamber. In addition overall station size was decreased, therefore decreasing lag and the incidence of the "Dispenser'd" glitch. Notably players would also be able to load the dispenser themselves, thereby keeping the dispensers full. When Gamma opened, the station became available for public use across the New World MRT Lines, and has been released for download. It is considered the most advanced - and least laggy - version of the MRT station. The original stations all have a similar architecture for their roofs (differs based on elevation), however the newer lines and extensions tend to have different architecture than the original stations and each other.
Version 5.1 was announced at the February 2018 GSM after a proposal by godzilltrain was approved. This change was a minor improvement to fix functionality that had been broken by a change in Minecraft's game mechanics. This upgrade allows the cart loader to be used, and also prevents carts getting stuck within the station, which had blocked departures from the station