Elvas Tower: Starting / Stopping Diesel Engines (Prime Movers) - Elvas Tower

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Starting / Stopping Diesel Engines (Prime Movers) Is this function used?

#1 User is offline   steamer_ctn 

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Posted 06 January 2020 - 02:20 AM

Recently whilst looking at the performance of diesel locomotives, I created a twin diesel engine (two prime mover) locomotive based upon the BR Deltic unit.

In the BR test report a series of test were done with either both of the prime movers running, or with one prime mover stopped. I noticed that OR enabled a user to turn a prime mover on or off. [ Shft-Y, turn player prime mover off/on, and Ctrl-Y turn helper prime mover on/off ]

So I decided to give this a go, and found that if I was running a train with a single diesel locomotive I could control either of the two prime movers with the above keys. However if I was running double headed locomotive I found that Shft-Y controlled the first prime mover in the leading locomotive, but Ctrl-Y controlled the remaining prime movers in both of the two locomotives, and thus it turned off all three of the remaining prime movers, resulting in the lead locomotive only being powered with a single prime mover, and no helper locomotive.

Similarly if locomotives each with a single prime mover are operated in multiple unit operation similar issues can occur. For example, a double heading operation (2 x locos) seems to work ok with the Shft and Ctrl keys controlling the lead and helper locomotives. However if more then two locomotives are run in multiple unit, the Ctl key will turn off all of the trailing units, and just leave the lead unit powering.

So as I haven't seen much discussion about this in the forums, I am assuming that users do not use the prime mover on/off function, and thus turning off all the trailing locomotives in this way is not an issue.

Is this the case?

#2 User is offline   ATW 

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Posted 06 January 2020 - 04:09 AM

Yeah it's true of those speed clicks turning off an on but I am sure some do the various of prime mover turn offs/on is the F9 key, click engine an power tab or disconnect MU tab to isolate traction only.

#3 User is offline   waivethefive 

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Posted 06 January 2020 - 07:17 AM

Here in North America our pursuit of double engine diesels ended in the late 60s, and unless there was a mechanical issue, both engines ran all the time. One of the negative aspects of double engines was when one prime mover had to go to the shop, it tied up the good one needlessly, which pretty much ended the fascination with double engines here. The genset era did briefly bring some of it back in the form of mini-prime movers whose power can be added and subtracted dynamically, but most have been failures.

In the late 70 and 80s, before AC traction and before DPU and before million dollar price tags on locomotives, we developed Select-A-Power, where an engineer could dial back any number of trailing units on the head end back to Idle as a fuel saver. They could be brought back to full power whenever full acceleration was needed, but once the train was rolling, they would knock the rear-most units down to idle and let the remaining diesels maintain track speed at more fuel efficient higher notch settings. It fell out of favor as AC traction and million dollar price tags became common. Tagging along extra units for acceleration moments only was okay when they only cost 200k, but as they started costing over a million, it became harder to economically justify this (mostly) idle acceleration-only horsepower just going along for the ride.

With the advent of higher traction units and better starting systems, rule books started changing to limit the number of powered axles for either acceleration or braking. Today, if you see more than 4 high adhesion locos on the head end of a train, some of them are shut down and off-line because the lashup exceeds the permitted powered axle count and remain so for their entire re-positioning journey.

With Auto-Engine Start Stop and DPU, if a train enters a siding for an extended wait, the two units in DPU communications will likely remain alive at idle but the other units MU'ed to the head end or mid-train DPU will go through AESS shut down. On some of our trackside rail cameras, I've seen the train take off from the siding with just the DPU units powered up while the AESS units have their warning bells and beepers squawking as they are going through the unattended prime mover restart phase, but the train actually starts moving again with all the units not yet alive again.

I have no idea how the same is accomplished in european operations, but I suspect it is not quite the same as train tonnages there are not similar to ours.

Something like AESS in the DPU era could be handled automatically in OR without any user interaction (just the right triggers in the ENG file combined with activity triggers), but select-a-power would require some user interaction to determine which and what quantity of units to dial back to idle on the fly. Other aspects like units dead-in-transit can be handled in an enhanced consist or activity editor, where the user determines which units are dead (or deliberately low on fuel, destined to go dry during the trip) during the creation of a consist or activity. Operational stats valid for that consist configuration only or for that activity only.

I'm all for accuracy, but sometimes I think we deep dive too much into certain areas like electrical efficiency while ignoring some of the more sexy and attractive aspects like adding DPU or AESS or Select-a-power functionality. You know the old saying, you don't sell the health benefits of steak, you sell the sizzle. There is sizzle we could be adding but find ourselves often a little too over-concerned with raw meat at the moment.

#4 User is offline   NickonWheels 

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Posted 06 January 2020 - 07:54 AM

Quote

So as I haven't seen much discussion about this in the forums, I am assuming that users do not use the prime mover on/off function, and thus turning off all the trailing locomotives in this way is not an issue.

Is this the case?


It would be an issue if it´s possible to start an activity with the prime mover shut down then you have to start it up first. Also the problem of missing sounds for starting, stopping and stopped engine as most diesels keep their idle sound when cutting out the engine. At last every such locomotive should have the option of controlling the prime movers independently regardless of a loco having one, two or whatever many engines. This also maybe the point to discuss multiple-unit operation...

#5 User is offline   copperpen 

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Posted 06 January 2020 - 09:45 AM

View Poststeamer_ctn, on 06 January 2020 - 02:20 AM, said:

Recently whilst looking at the performance of diesel locomotives, I created a twin diesel engine (two prime mover) locomotive based upon the BR Deltic unit.

In the BR test report a series of test were done with either both of the prime movers running, or with one prime mover stopped. I noticed that OR enabled a user to turn a prime mover on or off. [ Shft-Y, turn player prime mover off/on, and Ctrl-Y turn helper prime mover on/off ]

So I decided to give this a go, and found that if I was running a train with a single diesel locomotive I could control either of the two prime movers with the above keys. However if I was running double headed locomotive I found that Shft-Y controlled the first prime mover in the leading locomotive, but Ctrl-Y controlled the remaining prime movers in both of the two locomotives, and thus it turned off all three of the remaining prime movers, resulting in the lead locomotive only being powered with a single prime mover, and no helper locomotive.

Similarly if locomotives each with a single prime mover are operated in multiple unit operation similar issues can occur. For example, a double heading operation (2 x locos) seems to work ok with the Shft and Ctrl keys controlling the lead and helper locomotives. However if more then two locomotives are run in multiple unit, the Ctl key will turn off all of the trailing units, and just leave the lead unit powering.

So as I haven't seen much discussion about this in the forums, I am assuming that users do not use the prime mover on/off function, and thus turning off all the trailing locomotives in this way is not an issue.

Is this the case?


I think that most if not all who do switch power off and on, do so via the train ops window where each unit is controlled individually. I have not tried this method with the Deltic or Class 55, and in any case I have never seen a picture anywhere of these running double headed although they may have done for positioning. This does however raise a problem for anyone considering modelling a genset engine where there are up to 4 prime movers that can be switched in and out as conditions require.

Perhaps this total function can be moved into the train ops window with an on/off function for each prime mover on a chassis/unit.

#6 User is offline   darwins 

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Posted 06 January 2020 - 10:20 AM

The only UK case I am aware of where twin engined diesels were regularly double headed were Warships on the Western Region.
However turning on and off multiple engines might be a thing for diesel multiple units. First generation units generally had two engines per car and there could be several motor cars in a train.
Personally I am not given to turning engines on and off - in days gone by the seemed to leave them running most of the time.
Nowadays we are more concerned about wasting fuel and polluting the atmosphere - some modern units have engines that shut down automatically when left standing for some time and thus need to be restarted.


#7 User is offline   railguy 

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Posted 06 January 2020 - 01:12 PM

I use the F9 screen to isolate MU locomotives--it allows individual locomotives to be isolated or shut down. The problem with locomotive idle sounds persisting in a shut down loco is an .sms file issue. Most sound files have no provision for shutdown or start up because original MSTS did not have that option. A few .sms files have been built that do have shut down and start up, but they are pretty "clunky."

As to the discussion of AESS, I have wished (and so posted on the forum) that enabling AESS in OR would be wonderful. AESS, to function, though, would require the sim to monitor and logically process things like coolant temperature, external power demands (e.g. air compressors, etc.), reverser position, outside ambient temperature, and other factors. Even without AESS, EMD 710-engined locos, for example, also have a high-idle/low idle function that also relies on several of those parameters. That would be nice to have emulated.

#8 User is offline   ErickC 

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Posted 06 January 2020 - 11:21 PM

I use the feature a lot when testing freight cars, if only to justify the fact that the locomotive sounds I'm making these days have startup and shutdown audio!

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