Chinese developers this month tested a rail car-based launching system for a missile capable of hitting targets in the United States, a development that could make the system even more deadly, according to Potomac Foundation defense expert Philip Karber."If that missile train hosts the DF-41 ICBM it means it will also have a MIRV potential," Karber, whose organization recently identified one of the missile at a special launch site in Taiyuan, told The Washington Free Beacon. The combination of high-speed mobility, launch cars disguised as civilian passenger trains, tunnel protection and secure reloading of missiles, coupled with multiple warheads, makes the system extremely hard to regulate or verify the number of systems."The test was monitored by U.S. intelligence agencies, The Free Beacon reports, although Pentagon spokesman Cmdr. Bill Urban declined comment while stressing the Pentagon does "monitor Chinese military modernization carefully."There are few details available about the launch test, which occurred on Dec. 5, but similar rail-based missile development has been occurring at the Wuzhai test center, also known as Taiyuan, since 1982, according to declassified CIA documents.Other disclosures about the DF-41 have all shown it being deployed from a wheeled transporter on roads, but the rail car method could complicate preemptive attacks on nuclear forces.The DF-41 could carry up to 10 MIRVs, according to U.S. intelligence agencies, boosting Beijing's single-warhead stockpile, currently estimated at about 300 warheads.According to a report by Georgetown University's Asian Arms Control Project, China is believed to have gotten the rail-mobile technology from Ukraine, which built the SS-24 rail-based ICBM while part of the Soviet Union.In 2006, Chinese state television released early details about the train-based missiles, with footage shown of the railcars being disguised as passenger carriers.The Chinese dedicated missile rail and tunnel system could also avoid missiles having to fly over Alaska, where they could be shot down by U.S. anti-missile forces.The Pentagon is also exploring a mobile ICBM system, according to Air Force documents, but Rick Fisher, an expert on the Chinese military, said that nation has been interested in the program for some time."The Soviet SS-24 used a rail car launcher, could carry up to 10 warheads and had a range of 10,000 kilometers," Fisher said."This is close to the capabilities of the China Aerospace Science and Technology Corporation DF-41 ICBM."