CNGMotive’s new, purpose-built compressed natural gas tender resembles an intermodal well car.
Chris Guss
NEW CASTLE, Pa. – At a press event at Kasgro Rail’s New Castle, Pa., facility yesterday, CNGMotive unveiled the industry’s first compressed natural gas tender. Tender GCNX No. 5001 was built new at Kasgro for CNGMotive and features 28 separate CNG storage tanks in two groups giving the tender a storage capacity equal to 4,600 gallons of diesel fuel, also known as diesel gallon equivalent.
The tender design resembles a traditional intermodal well car, with the well portion used primarily for natural gas storage and the ends of the car over the trucks for the control system and pressure reduction system. The tender is setup to provide one or two locomotives with CNG while in service. Its design complies with the upcoming AAR Tender Specification M-1004 for crash worthiness, shock, and vibration.
When final assembly and testing of the tender is complete and Norfolk Southern receives their letter of concurrence from the Federal Railroad Administration, the tender will begin revenue testing between Williamson, W.Va., and Lamberts Point, Va., in export coal service. NS is borrowing BNSF SD70ACes Nos. 9130 and 9131 for the tests since NS has no six-axle locomotives equipped with dual fuel equipment. Both locomotives are currently in Alliance, Neb., being worked on prior to shipment to NS. While BNSF used these locomotives for liquefied natural gas testing previously, no additional modifications are needed for compressed natural gas testing. Regardless of the storage medium a tender uses, compressed or liquefied, the associated equipment on a tender converts the gas to its ready-to-use form prior to sending it across to the locomotive for combustion.
NS hopes to being testing later this year or early 2020 with the new CNG tender with a planned minimum six month test period. Refueling will take place at the midpoint of the test corridor at Shaffer’s Crossing in Roanoke, Va., by Roanoke Gas Co. The tender will refuel on both the loaded and empty side of its loop. CNGMotive will use a patented Chill Fill technology during the refill process which will reduce the refill time to under an hour by increasing the fill rate by approximately 10 times the traditional rate.
This is what, the fourth time they’ve tested this?
Thanks guys for the feedback. I agree with Doug that perhaps TRAINS Mag can do an in-
depth study comparison between CNG, LNG & diesel. Costs, exhaust, DGE, volumn, etc.
I would imagine that an engine burning either CNG or LNG would have fewer emissions than diesel fuel and make the EPA happy.
I’m a close follower of the FECRW, and know they have used LNG sets for several yrs, with good success. Not being an expert, I’d love to see an article comparing LNG and CNG. I do know that “some” diesel is always mixed with the gas, and more gas is used at higher speed, making it not as efficient at lower speeds as a switcher or “local” train might use.
Roger Cole, burning NG produces fewer (really none) particulates than diesel, but the 2 primary results of NG combustion are CO2 and H2O, both of which are greenhouse gases (well, water vapor, not liquid water, of course) .
The benefit to RRs is strictly cost, rather than environmental. Clearly, NG is still less convenient than diesel, based on the volume of storage, time to reload the tanks, and the energy equivalency,given that it takes an entire railcar to store less than the amount of diesel today’s SD locomotives can hold in their inboard tank.
I hate to think what would happen in an accident with on of these in every train.
One thing, “DGE” is Diesel Gallon Equivalent, not Gallon. Hope it works!
Charles – the rough rule of thumb is that on a volume basis, LNG needs twice the space as diesel fuel, and CNG 4 times the space as diesel. The beauty of the tenders is that they do allow a competitive amount of CNG to be stored so as to enable longer distances between refuelings – especially with the natural gas burn rate of current dual-fuel locomotives. With dual-fuel locomotives, CNG tenders can roughly double their range, so Chicago to LA un-refueled is possible when accounting for the fact that the dual-fuel locomotives have an average substitution rate on the order of 60% across a locomotive duty cycle. With some development work on locomotives and tenders beyond today’s rail state-of-the-art (but with technology that has already been tested in other arenas) it is theoretically possible to go from Chicago to LA on 100% CNG un-refueled with one tender shared between two locomotives…
Natural gas is also safer than many people think vs. something like propane as you stated. Natural gas will only ignite in air mixtures from about 5 to 15% natural gas to air. Outside of those bounds it will not burn. Those same properties also make it MUCH less likely to go “boom” (despite sensational headlines to the contrary) and the tenders are required to include multiple safety layers to prevent such things from occurring.
Ian, John, and Jim: To add to what Wolfgang has provided about CNG being a lower cost than LNG, the trade off is density. The cubic volume of the CNG car is equal to about 4,600 gallons DGE per the article. In a similar space an LNG tank would hold about 15,000 gallons of DGE fuel if my memory is correct. Wolfgang may know a more accurate amount. One of the appeals of using LNG would be that to cover an existing route, say Chicago to LA would require fewer fueling stations if LNG was used instead of CNG.
In regards to the explosive issue what typically comes to mind are some of the propane gas derailments. A difference is that natural gas is lighter than air so if released it will dissipate up into the atmosphere. Propane is heavier than air so the gas spreads out along the ground to where it can more likely find an ignition source such as a burning derailed locomotive. Of course if the NG is released and it does find an ignition source, things will get ugly real quick.
Ian Narita: the crash-test requirements for the tenders are quite rigorous and are based on real-world accidents. Numerous other safety features were included in the AAR M-1004 standard governing their design.
John Winter: because they were envisioned to run in-between locomotives from the start, the CNG and LNG tenders are engineered to safely live in that environment…I will let others comment on the PHMSA regulations concerning the buffer cars…
Jim Jones – simply put, economics. Price swings in the crude oil market circa 2016 decreased the price differential between natural gas and diesel to the point where natural gas was less attractive. The market has recovered a bit now and the long term predictions for the price differential favor natural gas. CNG typically enjoys a 30 cent or so lower cost per “Diesel Gallon Equivalent” (DGE) than LNG because of the extra energy needed to take the natural gas down to temperatures where it becomes LNG.
This is intriguing and all that, but why have other railroads like BNSF put it on the back burner after testing LNG? I know that LNG is different from CNG but I don’t know enough about either to make a comparison. Could someone shed some light on this?
Question….In an oil tank train a buffer car is places between the tank cars & the engines. But with these CNG & LNG tenders, they are placed between the engines obviously to fuel the engines. Looking for clarification. What’s the difference why a buffer car is needed in one circumstance but not the other? Is safety not an issue with one compared with the other?