Later this year, China is going to conduct its first exercise in which divisions from four of its seven military districts will move long distances (in one case, 2,400 kilometers) using their own vehicles, and conduct combat exercises together. Air force and army aircraft will be involved, as will modern (satellite based) communications and electronic warfare. This is all new for the Chinese, who have been using century old strategic concepts (railroad movement of non, or semi, mechanized units to a concentration point near the battlefield) for over 60 years. Since World War II, Western nations have fully motorized their armies, so that, if need be, the divisions can move, using their own vehicles, thousands of kilometers. China is mechanizing its army a division at a time, and over 70 percent of their 60 divisions at least motorized (with trucks, not armored vehicles). But until now, China has not tried moving these motorized and mechanized divisions long distances on their own, except in emergencies. This was the case last year, when a "quick reaction division" was moved into Tibet to suppress riots, and 130,000 troops were mobilized for disaster relief work after massive earthquakes in central China. In that case, however, the troops did not move their weapons, or most of their equipment.
It is still common practice for most nations to move mechanized divisions long distances by railroad. The railroad eliminates most of the "road fatigue" for China's mechanized infantry divisions. These units contain 600 armored vehicles, plus several thousand trucks. Moving long distances is not that hard on the trucks, but it is hell on the armored vehicles, since most of them run on tracks (like a bulldozer).
Some Chinese mechanized divisions are designated as "rapid reaction" units, and are kept at a higher state of readiness (repairs on made on vehicles promptly and fuel and other supplies are kept on hand so some portions of the division can be sent off within hours of getting the order). These units also have a third or half their 350 tracked vehicles (BMP clones) replaced with T-90 wheeled armored vehicles (like the U.S. Stryker). These survive long road movements better than tracked vehicles, they are still heavy (15 ton) vehicles, and some will break down when covering long distances. A typical mechanized division weighs about 15,000 tons. So it would take less than two days to move a division several thousand kilometers over a single rail line, and there would be little wear and tear (most from moving a hundred kilometers or so to the railroad).
This training exercise enables China to test their ability to rapidly move combat units by road, if Russian or Taiwanese missiles cut rail lines (by dropping bridges or blocking tunnels.)