sold out. These were the somewhat infamous first-generation RC train sets that superseded the 9V System t rains.
Both sets featured locomotives designed around a large train baseplate with an integral 6-AA battery box and IR receiver. Both sets were introduced in 2006 and had been available for nearly 4 years. For a majority of that time, these sets were the only LEGO train sets available other than those that could be designed using LEGO Factory (now called Design byME).
Although these battery-powered train sets were touted as a simpler way for children to experience LEGO trains, these sets were highly controversial in the adult LEGO fan community. The sets were seen as an inferior substitute to the 9V System due to lower motor performance and limited run time due to the use of batteries instead of a wall transformer for power. Additionally, the integrated battery box / receiver / train base unit limited further design possibilities. It was claimed that the battery-powered IR sets would reduce the cost of LEGO train sets relative to 9V. At 90 USD for the Passenger Train, this set was marginally less expensive than comparable 9V sets, while the 150 USD price of the Cargo Train set made it as least as expensive as its 9V predecessors.
The 7897 Passenger Train earned an even more dubious reputation due to what can only be described as a design flaw in the molds used for the large, one-piece elements making up the nose and windshield on each end of the bullet-style train. Those who purchased this set surely noticed that these elements did not come together squarely with other bricks when attached to the train.
Both sets appear to have been influenced by real European prototypes. The style and colors of the Passenger Train are reminiscent of the German ICE high-speed train, while the cargo locomotive is similar to the Krokodil design of Swiss origin. This engine may be seen as an homage to the 4551 Crocodile Engine, a fan favorite which enjoyed a fairly limited production run. The engine in 7898 uses the same front window elements as the Crocodile Engine but introduces them in a new color, green with trans-smoke glass. These elements - and others, such as green train doors, a 2x6x2 sloped train windshield - made 7898 a set with appealing elements and design possibilities for older builders, while the 7897 Passenger Train was seen as an entry-level set for younger builders.
The retirement of 7897 and 7898 means that the Emerald Night is the only complete LEGO train set currently on the market, although train sets can still be designed using the LEGO Design byME palette. This development is not altogether surprising; it had been rumored that the first-generation RC train sets would eventually be replaced by new train sets in the LEGO City line, and these new sets would do away with the integrated train base / IR receiver module. It is possible that future LEGO train sets will also eliminate the RC speed controller found in 7897 and 7898. By all expectations, future LEGO train sets will continue to use the current all-plastic RC train tracks and battery-powered train motors. It will be interesting to see if the motors are updated for compatibility with the Power Functions line; the motors found in 7897 and 7898 used a 9V-compatible power connector.