The new "Jet Train"

[Anonymous]

I am all for improvements in passenger rail, but looking over the piece covering this "new" concept, I am reminded of the French turboliners of the early 1970's. The trains themselves were up to the task, but congress wasn't. I think that us taxpayers buy any more "$1000.00-toilet-seats", we need to be sure that the infrastructure, and backing will be there to support these new trains. Here in Michigan, in the 1970's, the turbos were brought out with much fanfare, and thought to be the answer to Amtrak's Ills. But, alas, those 125 MPH trains spent their lives rocking down poorly maintained track at no more than 79 MPH. Considerably less, in some places.
Now, if someone has change for a nickle, that was my two-cents worth.
Todd C.

[Anonymous]

I'm wondering if someone can offer info on something I'm wondering about re: the "Jet" train. Being "turbo" it reminds me that Union Pacific experimented with turbo in the 50's and early 60's as well but I understand the locos ended up being scrapped. Is Turbo now a valid alternative to "standard" internal combustion, and yes, how so?

[oltmannd]

The pros and cons of gas turbine powered locomotives:

Pros:
-very high power to weight ratio. This is important on a couple of counts. For high speed passenger operation, you need a very high ratio of HP to continuous TE, so any extra weight is just a burden. A state of the art 5000 HP diesel locomotive would wind up weighing ~300,000#, about double it would need to be for performance. The light weight also makes the locomotive easier on the track structure - an essential feature for high speed operation. Two F40s could do the job of one JetTrain, but they'd be lugging around an extra 200 tons and be limited to about 110 mph or so because of track forces.

-very low emissions. Diesel ain't bad, but gas turbines are nearly perfect.

-very few moving parts (like, one), versus several hundred for a 16 cyl diesel engine.


Cons:
-high idle fuel consumption. A F40 will make 3000 HP buring 160 gallons an hour, but idle at 3-4 gallons an hour. A gas turbine burns about 1/3 full throttle fuel at idle. This is a huge issue for frt RRs where locomotives are in idle >50% of the time. Presumably, this is less of an issue for high speed passenger operation where trainsets are turned quickly and need nearl full throttle operation for long stretches and make multiple trips per day - and can be shut down otherwise.

I think Bombardier may be a bit early to market with this JetTrain, but it can fit into a plan that develops a network of semi-high speed routes (110-125 mph, maybe with some higher speed dedicated ROW) alongside and integrated with existing frt ROW, particularly east of the Mississippi where there are lots of 500,000+ cities a couple of hundred miles apart. Not having to electrify saves huge bucks! (And allowing frt RRs to share some of the benefit of a higher speed infrastructure will open new market for them and enable them to kick in some bucks towards the upgrading)

I remember when NY purchased those French derivative Turboliners for Amtrak service in the late 70s. Very nice train sets - smooth and quiet. With NY paying, Conrail upgraded Poughkeepsie to Albany for 90-110 mph operation - class 5-6 track with 6" superelevated curves. Hitting those curves at speed felt very much like flying! Albany-Rensselaer Sta. smell a lot like an airport, too....

[oltmannd]

Lots of good stuff about JetTrain at Bombardier's web site including video.

[Anonymous]

One of the most interesting technological goals of this program seems to have been abandoned. In the initial proposal the locomotive was supposed to have been equipped with a ceramic flywheel using superconducting,electromagnetic bearings. This would act as a superbattery to store energy in kinetic form. It would store the rheostatic braking system energy for traction use(regenerative brakes) and would also mean that the turbine-generator could be turned off,rather than left in idle. Such a system would allow starting acceleration curves comparable to a straight electric locomotive because you could tap power from the flywheel rather than having to wait for the turbine to "spool up" to get maximum traction current. This hybrid system sounds like it has a lot more potential(both with gas turbine and diesel powerplants) than a "simple" turbine -electric.

[oltmannd]

I think the flywheel idea is a good one, but there is no off-the-shelf technology, unlike the gas turbine they're using that's been around the block a few times. I think the main benefit of the flywheel would be energy conservation. For intercity passenger service, being able to accelerate a bit faster won't shave much off the schedule. You're pretty much limited to 2.0 mph/sec for passenger comfort, anyway.

Wonder what the spool-up time to full load is for the gas turbine. It's about 30 seconds for and EMD 645 engine and 80 seconds for a GE FDL (with more than half the HP coming on in the last 20 seconds of that 80! - anybody buys a GE for commuter service should have their head examined - hello, MetroNorth!)

-Don

[Anonymous]

Donald, Thanks so much for the information you provided on the pros and cons of turbine engines. This is exactly the kind of information I was looking for and helped answer the questions I had on turbine vs. diesel. Thanks again, and best wishes, Capers

[Modelcar]

This new concept [different], than the diesel electric sounds interesting. In fact any advancement in Passenger rail activity is welcome reading. My hope is TRAINS will grab the story soon and generate a feature on it...along with perhaps a cut a way of the engine and it's mechanical workings.

QM