For the last few months North Korea has had many of its TELs (Transporter Erector Launcher) in motion and moving around the country. This provided an opportunity to get a better look at the North Korean TEL fleet, and it became clear that there were about twice as many TELs up there than previously thought. Now U.S. and South Korean intelligence agree that North Korea had about 200 TELs, not 94 as previously thought. About half of the TELs carry SCUD type missiles (with a range of about 500 kilometers) while a quarter carry the larger Nodong missile (1,200 kilometer range) and the rest carry even larger Musudan (over 2,000 kilometer range) and a few KN-8s (over 4,000 kilometers).
It was only in the last year that TELs carrying the KN-08 (also known as the Taepodong-2) were seen. This large TEL and its missile first appeared a year ago, in a North Korean military parade. There for the world to see was a 16 wheel TEL carrying what appeared to be a three stage ballistic missile. Both the TEL and the missile had not been seen like this before. What was odd about the KN-08 was that it had only been tested once (in 2006) and that failed. North Korea has never been known to deploy a long-range missile that had not been successfully tested. Some thought KN-08 was a fake, just something to make the cold, hungry, and broke North Koreans feel better about themselves. Markings on the TEL identified it as “Hwasong-13 Self-Propelled Launcher.” There are two other North Korean Hwasong missiles, both of them short (up to 500 kilometers) range liquid fuel rockets. These two were called Hwasong-5 and Hwasong-6. Defectors from North Korea indicate that the official name for all North Korean ballistic missiles is Hawsong and that indicates that a missile named Hwasong-13 could be the latest one.
What was also interesting was the TEL, which is a large truck specially built to carry, then erect and survive the launch of a ballistic missile. The North Korean TEL was unlike any seen before but the cab was similar to a Chinese heavy transporter. North Korea apparently bought these heavy trucks and then modified them into TELs. This is what Iran did for a long time, until sanctions officials ordered heavy truck manufacturers to stop selling Iran the big vehicles that could be converted to TELs by the buyer. It was later revealed that the North Korean TEL was based on a Chinese vehicle exported to North Korea.
Large trucks modified to be TELs are often not real TELs. There are a lot of manufacturers out there who build huge (12-20 wheel) trucks, and these are often used to carry military equipment (like 60 ton tanks). A 12-50 ton ballistic missile is no problem but installing the hydraulic gear and controls to erect the missile to a vertical position is tricky. Even more difficult is hardening the rear of the vehicle to minimize the damage from the rocket exhaust. This last bit can be dropped if you only expect to use these TELs once for a live fire. The 16 wheel North Korea TEL may have been one of those "use once and abandon the trailer" models.
It is believed that the TELs and their cargoes are being moved around to build North Korean morale and to mess with foreign intelligence agencies. North Korea has been observed carrying on like this before but never on such a large scale. The North Koreans assume that the U.S. and South Korea know where the fixed missile launching sites are and plan to hit them with smart bombs in the early hours of a war. But the mobile TELs can avoid detection for a while, often long enough to launch their missiles at key targets (air bases, headquarters, etc.).