I know GM engines had 2 electric starting motors, but I also know some engines used air to start.
What do current locomotives use? GE's or EMD's.
Thanks for any answers.
Depends on the locomotive type. Units with DC main generators usually just use the generator to start and do not have separate starter motors, but units with AC main alternators (normal for higher horsepower units since the mid 1960s) usually cannot do this.
MLW used air starters for a while, then went back to electric.
GE has always used electric start in one form or another. I think they use the auxiliary generator as a starter now, but I'm not sure.
EMD went to air starters when the SD70ACe and M-2 were introduced circa 2005, I believe I've heard the SD80MAC also used this method due to the larger size of the engine being too much for the electric starters they used.
I think EMD went back to electric start for the SD70ACe-T4
If an air start unit shuts down the air will leak off relatively quickly, so we aren't allowed to manually shut down consists that have only air start units, just leave them isolated and let AutoStop do what it wants. Our SD70M-2s are also being retrofitted with backup electric starters, but still use the air starter as the primary method.
Having said that, it is much easier to boost an air start unit out in the field. Just couple another unit to it and connect the main reservoir hose. You now have unlimited tries at starting the dead engine, and don't have to worry about overloading or burning out the starter.
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In the olden days when Diesel engines used mechanical injection the decision came down to using battery to roll the engine vs. main-reservoir air. If you were a railroad like PC, good batteries cost more than pumped air, so there could be advantages to Alco air-turbine start that cost extra over motoring the main generator or whatever. With EFI and the rise of computers, having reliable battery power at what might be substantial minimum voltage takes away some of the advantage of a pure air start.
There used to be a noise penalty associated with air starters, which might rule out their use as prelubers a la Caterpillar (where the starter Bendix drive is kept disengaged and the prelube pump is driven by the starter motor).
CSX Fuel Conservation instructions were that if a train knew it was going to be stopped for over 30 minutes - engines except the leader were to be shut down for fuel conservation. Crews were expected to have locomotives restarted so they could move on after their stoppage without delay.
From a purely selfish point of view - I wish locomotives were equipped with BOTH electric and air starters. When batteries die it cannot be started unless heavy duty jumper cables are available - such cables are not stocked on locomotives, the mechanical department has to be called to jump the engine with dead batteries. Were the engine also equipped with a air starter - the Main Reservoir air pressure in another working engine can be used to charge the air starter.
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All EMD locomotives with DC main generators used the generator to start the engine. The pair of Delco electric starter motors were introduced with the AR10 alternator in the 40-series models and were carried thru the 70 series until the SD70ACe was introduced, which had air starters. The 710 engines in the 60 series developed problems with leaky exhaust valves as they aged, which made them hard to start. The twin electric starters could only spin the engine to about 60 rpm reliably whereas the engines with leaky valves needed about 70 rpm to start. I recall some engines got retrofit with air starters, which spin the engine faster, and some got two additional electric starters for four total but I don't know which or how many.
The Tier 4 1010J engine was designed from the outset to mount the alternator to the engine and there is no provision for a ring gear and electric or air start motors. It uses a solid state device to spin the alternator, like GE has done for years, for starting. Some or perhaps all the SD80MAC's had an earlier version of alternator start but it was too expensive for widespread use.
Dave
BaltACDFrom a purely selfish point of view - I wish locomotives were equipped with BOTH electric and air starters.
Or they could just let the auto-start systems do their job. I think the engineers at EMD/GE probably knew a bit more about this than most RR managers.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
BaltACD From a purely selfish point of view - I wish locomotives were equipped with BOTH electric and air starters. When batteries die it cannot be started unless heavy duty jumper cables are available - such cables are not stocked on locomotives, the mechanical department has to be called to jump the engine with dead batteries. Were the engine also equipped with a air starter - the Main Reservoir air pressure in another working engine can be used to charge the air starter.
I had an air start engine has a mid-train DP once. The auto stop shut it down. When it was time to go, the air had bled down so that there wasn't enough for it to start back up. A mechanical dept guy came out. He had a short hose with a train line glad hand on one end and a MU hose glad hand on the other. He was able to recharge the dead engine with train line air this way and get it restarted.
There used to be a requirement that DP units were to have auto stop/start disabled. It's either been removed or just hasn't been observed, for quite a while now.
Jeff
zugmann BaltACD From a purely selfish point of view - I wish locomotives were equipped with BOTH electric and air starters. Or they could just let the auto-start systems do their job. I think the engineers at EMD/GE probably knew a bit more about this than most RR managers.
BaltACD From a purely selfish point of view - I wish locomotives were equipped with BOTH electric and air starters.
Auto-start is a 'relatively late' invention (last 15-20 years).
I've run into a number of units (both EMD and GE) over the years where AutoStop shut the engine down and then failed to restart it for one reason or another, weak batteries being a common cause.
I don't think I've ever encountered one with totally dead batteries out in the field, though of course this could happen if you left it for long enough. They always had enough juice left to run the computer and other little stuff.
The computer gives up rather easily when trying to start a unit with weak batteries, once the voltage drops below a certain level it quits, even if the engine has started to roll over. Or it quits cranking after so many seconds, presumably to save the starter.
On older units with manual start switches you can keep trying for as long as it takes (I remember one cold GE that took almost a minute of cranking before it fired).
I agree with Jeff about the DP remote issues, we too have been told several times over the years that AutoStop is supposed to be suspended when a unit is set up as a remote, but reality proves that to be wrong on a daily basis.
oops double post again
Going to check this out. CSX is parking a crew less train here about every 4 - 5 days including some trains with a DPU. Since the trains have to be split for grade crossings will have some interesting observations.
BTW what is normal warm up time for various models.?
If the engine was at room temperature when started it can take several hours of idling before the "Load Limited, Cold Engine" message on the computer screen goes away.
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