Idling Diesels

Why are diesels allowed to idle constantly? Thousands of gallons of fuel are being waisted and tons of pollutants are released into the atmosphere each year. My state (Pa.) has a law prohibiting diesel powered vehicles over five tons from extensive idiling, are locomotives exempted? Am I missing something or is there a sound reason for idiling 24/7? I know diesels are hard to start when cold but preheating systems are available. We have ether injection on our Cat powered (antifreeze filled)locos and an electric heating system on our EMD loco.
I know there are 'green' locos that shut down to save fuel and restart to deal with changing conditions. Is cost the issue, or does convience call the tune?

Idling has been the practice since the beginning of diesel locomotives on the railroad, not that it justifies it at all. Historically, when power is at the ready, it is started and running. The oil is warm and as soon as the crew walks in the door it is ready to be put on line and go... that's called expediting. This formula is accurate for fuel consumed at idle for a decent running EMD: 1 quart of diesel fuel per cylinder per hour. Idling excessively isn't healthy for an engine internally and causes excessive carbon buildup in the exhaust manifolds and lube oil to be burned (or unburned) and thrown out of the exhaust stacks all over the place and whatever is in the area. But then again, not too many locomotives idle all day and night nowadays, except in winter...

The first situation, without a doubt, is weather specific. Most modern locomotives are equipped with an automatic start/stop system that will shut down the locomotive and then restart it before critical minimum levels are reached - ie coolant temperature, air pressure, battery voltage levels etc. Older locomotives can be outfitted with a "hot start" system which accomplishes the same things, and are reasonably priced considering the fuel saved, I would imagine. Locomotives that are not equipped not only are very difficult to be started when ice cold, but leaving an engine with water coolant (because no railroad except short lines wish to put hundreds of gallons of high quality antifreeze in their locomotives) shut down for extended periods of time in sustained low temperatures below 35 degrees shatters pipes and cracks prime mover engine blocks. Most railroads have some sort of standard that calls for locomotives in yard and sometimes road service, situation dependent, to be shut down when they will not be used for over (approx) 45 minutes to 1 hour and ambient temperature is above 35 or 40 degrees. In the same way, if an engine dies with an ambient temperature below or expected to drop below 35 degrees and can't be restarted, it must be drained to avoid the damage described above. Get into really extreme low temperatures ie -10 to -30 F you'll find engines "idling" in Run 3 or 4 because they can't keep themselves warm while sitting.

Another situation - "pumping air" or keeping a train that has received an air test charged. Shut down locomotives attached to that train and eventually the air is going to bleed off. Let brake pipe pressure fall below 60psi and the 90 car air test your conductor just walked is void if left that way for over 4 hours. For example: the time elapsed between the minute you tied down a train after going dead and the time it takes the next crew to cab out to get the train. I was that second conductor many times... very annoying.

I can go on with the examples, but as you said it probably boils down to implemtentation costs for older locomotives versus the life they may have left in them on a particular railroad. As for the PA state law, I have no idea.

The PA law is full of loop holes, ie. if the truck has a pto (All dumps & most commercial trucks, but not plain semis) it is exempt. I would be very surprised if applied to anything other than on road vehicles.

There are a few other considerations in addition to the ones Mike made.

There are two basic engine heater systems used, not counting the built-in autostart systems on late model locomotives. Both of these are retro-fitted to older units.
The first type is an electric heater similar to a tank heater or block heater you can install on your car. You shut down the locomotive engine and plug it in. Pretty simple and foolproof, unless you have to leave the locomotive parked somewhere it can't be plugged in.

A hotstart-type system. This uses a small Diesel engine mounted in the air compressor compartment. When the main engine is shut down, this little one starts up if the water temperature falls below a certain level. The cooling water from the little engine circulates through the locomotive's cooling system, keeping everything warm.

The factory-installed autostart systems on the newer locomotives work on a timer. They will also come on if the trainline pressure falls below a certain level. FRA rules require a new air test (Mike's 90-car walks) if a tested train or block of cars is left "off air" for four hours or more. So these are about keeping air tests good as well as protecting engines from freezing.

It all comes down to the bottom line. Antifreeze is expensive. So is bearing replacement, which is what can be needed if a leaky engine mixes antifreeze with lube oil.
Diesel fuel is expensive, too. So is paying conductors and brakemen to walk long trains doing extra air tests.

Engines left idling for long periods experience carbon and oil buildup in the exhaust stacks. The oil blows out, all over the units. It gets on windows, walkways, handrails, hood sides. It takes time (and therefore, money) to clean this mess off just to make the locomotive safe to operate and work on. It also gets all over everything left outside in the vicinity of the locomotive, including your car!

And that same accumulation can result in a stack fire when the engine is worked hard.

Les

Most railroads are good about shutting down there units in the Spring-Early fall but then keep them up and running during the winter months up here in New York. If and when possible I have also seen whole trains shut down and hooked up to big air compressor's in yards before as well.

Even on the Sperry Cars them selves when parked we had a small 4 cyl Lambo that we used at night for power and also to keep the fuel warm and the air compressor running. During the day we would shut that down and switch over to a CAT 3306 which powered everything but the drive truck which was handled by a CAT 3304.