With all the CNG (Compress Natural Gas) powered buses, shuttles, trucks and some cars. Maybe we will see CNG Powered Locomtoives. I live in LA where I have seen a ton of CNG Buses. I have now want to see a Locomotive running on CNG. But CNG powered Vehicles are about 40 heavier then a normal powered vehicles. For Example: A Neoplan CNG has 16 to 20 CNG Tanks and a very heavy steel plate to protect the tanks from objects hiting them. the only other problem with CNG is that they have a small stalling problem. But that only happens when they and switching tanks. But the Big Issue is the Price Tag of the Vehicle and the CNG fuel it self. The Price Tag for a CNG is high then another fuel powered vehicle. MTA has paid about $400.000 bus a CNG Bus. A Diesel Powered Bus is about $195.000. the other problem is training people to fuel these Vehicles. Like what happen to MTA Bus # 4519. A person was refueling 4519. But put too much pressure in the tank and 4519 exploded. No one was killed. But the person refueling was injury. Atfer that happen. The MTA took all the CNG Bus fleet it has at the time. Off the Streets until the problem was solved. Its was funny to see a Orange County Transit Bus running on a MTA Line and seeing San Juan Capistrano on its Head Sign. I like CNG Buses. they burn 98% cleaner then Diesel Powered Vehicles do. But the High Price Tag is limiting the production of more CNG Vehicles. Right now CNG Fuel is a Experimental Fuel. Funny we had Bus Companies and other like Super Shuttle, Southern California Gas Co, LA DWP and other Companies to buy CNG Vehicle. Until the Experimental Label is taken off the CNG. The Price Tag will be very high. I would love to see An Amtrak, UP and BNSF CNG Units. We have already seen tests with LNG gas Units by M-K Like the MK-1200 and 5000. But there are not a god number of LNG Units right now.