The in the name TRAX stand for the members stage names
Typhoon
Rose
Attack
X-Mas
Their names also stand for Typhoon of the Rose Attack on Xmas
The TRAX is active in both South Korea and Japan. However, the band is not widely recognized in South Korea because the rock genre does not play a big role in the Korean music scene. The band made a brief mark on the Korean charts in 2006 with their song "초우 (初雨)," (First Rain) a rock ballad, from their first album. The band also does not have a strong presence in the Japanese music scene because of the over population of rock groups and the recent flood of Korean singers trying to make their mark in Japan.
On September 3, 2006, Choi Si Won of the group Super Junior filled in as the support drummer for a performance of "초우 (初雨)" on "SBS Inkigayo".
Typhoon
Typhoon (born April 8, 1984) is the leader and main vocals of the band. He is also known as Jay Kim. Typhoon grew up in California, U.S.. Typhoon has often called Kim Hee Chul of the group Super Junior his "girlfriend". The two have been good friends while living together since their days as SM Entertainment trainees.
Attack
Attack (born June 15, 1985) plays the bass for the band. His birth name is Kang Jung Woo (강정우) and going by the nickname "Dul Bong". The instrument he uses is ZON's Sonus5 (SVT Classic).
X-mas
X-mas (born March 26, 1985) plays the guitar for the band. His birth name is Kim Jung Mo (김정모) and going by the nickname "Gammo". The instrument he uses is Zemaitis GZ501-Heart/BK Electric Guitar.
Rose
Rose (born May 29, 1986) played the drums, and was the back-up vocals for the band. Rose's real name is No Min Woo (노민우). On May 10, 2006, Avex Trax announced on their official website that Rose left TRAX to pursue other interests. He is currently the guitarist for the underground four-member rock band "The Romantist". He attends Inha University and studies art.
(information from Wikipedia)

(from left to right: X-mas, Rose, Typhoon, and Attack)