Steam generation depending on boiler pressure?

[Pizzaguy]

I know a bit about steam locomotives but what I wanted to know is if I can use the steam pressure as a sort of reservoir - that is to run it to about 50 percent pressure and let it regenerate when stopping at a station to get more oomph out of the locomotive and not waste steam generation on a blown safety valve? I don't know if this will effect overall steam generation due to the lower pressures or if the pistons don't work as efficiently.

[kubanskiloewe]

i noticed its much more effective to run pressure near max than reduces pressure and open the regulator more.
My best settings are 35% power to the wheels and 50 gradually down to 25%-35% regulator.

imho you cant run max speed with only 50% steam pressure.

[Pizzaguy]

Originally posted by kubanskiloewe:

i noticed its much more effective to run pressure near max than reduces pressure and open the regulator more.
My best settings are 35% power to the wheels and 50 gradually down to 25%-35% regulator.

imho you cant run max speed with only 50% steam pressure.

yeah ive actually gave it a try you loose a lot of speed at 50 percent pressure
now I am just curious what mechanism in the steam locomotive causes this effect

[mca0004]

Originally posted by Pizzaguy:

yeah ive actually gave it a try you loose a lot of speed at 50 percent pressure
now I am just curious what mechanism in the steam locomotive causes this effect

Well, basically, steam locos work through, well, steam. Boiler pressure indicates how much steam is currently in the locomotive, which is why the safety valve will blow off once there is too much (and why a loco will explode in the absence of one). If boiler pressure is low, it means there isn't a lot of steam in the system, and therefore, not a lot of steam can go to the cylinders and pistons.

[Sim Guide]

The main reservoir of energy in a boiler on a steam locomotive is in the water. To build up that reservoir of heat in a measured way, to not waste coal or steam (or time), you need to add water. But you cannot do this in Spirit of Steam (yet) because water management is not (yet) modelled.

It is a major failing of this DLC - to release it so shamefully incomplete, without water management. Without coal/firing management. And with uncontrolled delivery of fire, so that the pressure valve is blowing at the start of every run, whenever you reach line-speed and you have no demand for power, whenever you are shunting at low speed, and at every stop. To make matters worse (the unbearable sound that swamps all of the other audio), the pressure valve doesn't even release any pressure, so there is little respite....!

Both locos in this DLC have been very poorly simulated, Apparently the blower is being used by some people to smother the fire (when in reality the blower would fan the flames...). And the lever for the cylinder drain/taps is implemented the wrong way around (I am fairly sure that forward and down is closed, in reality, on these Staniers). It is almost as if this is the first time anyone has tried to model a steam engine in a train simulator, and they have no reference materials, books or experience to make a fair stab at it....

[Pizzaguy]

Originally posted by Sim Guide:

The main reservoir of energy in a boiler on a steam locomotive is in the water. To build up that reservoir of heat in a measured way, to not waste coal or steam (or time), you need to add water. But you cannot do this in Spirit of Steam (yet) because water management is not (yet) modelled.

It is a major failing of this DLC - to release it so shamefully incomplete, without water management. Without coal/firing management. And with uncontrolled delivery of fire, so that the pressure valve is blowing at the start of every run, whenever you reach lines-peed and you have no demand for power, whenever you are shunting at low speed, and at every stop. To make matters worse (the unbearable sound that swamps all of the other audio), the pressure valve doesn't even release any pressure, so there is little respite....!

Both locos in this DLC have been very poorly simulated, Apparently the blower is being used by some people to smother the fire (when in reality the blower would fan the flames...). And the lever for the cylinder drain/taps is implemented the wrong way around (I am fairly sure that forward and down is closed, in reality, on these Staniers). It is almost as if this is the first time anyone has tried to model a steam engine in a train simulator, and they have no reference materials, books or experience to make a fair stab at it....

I haven't tried without automatic fireman off, there is an option that might be under a different name in the menu I don't know if that makes you able to manage water levels

[Sim Guide]

Originally posted by Pizzaguy:

I haven't tried without automatic fireman off, there is an option that might be under a different name in the menu I don't know if that makes you able to manage water levels

When you have selected manual control of the fireman you can additionally control the damper doors underneath the fire (two levers on the floor on the right of the cab), and the blower (lever in the middle of cab at hand height). Opening the dampers enables more air to flow through the fire when you are using power, with the regulator open (which also generates draught). The blower can be used to feed an air draught onto the top of the fire when the regulator is closed, to enrage the fire when you are at standstill, should you want to.

Manual control does not currently let you control the amount of coal added, so you cannot control the energy input. It also doesn't allow you to control the supply of water and build up a reservoir of heat from the coal that is automatically piled on at an excessive rate. Both of these actions are fundamental to a steam simulation, so the DLC was not ready to be released or sold. Ideally there would also be a limited supply of water, so that you have to manage it properly. The safety valve(s) should only open if there is a monstrously high excess of steam from a nearly empty boiler, or if the boiler is full of water and the fire is ridiculously hot (and has been so for a very long time). Emergency safety valve blowing is not something that happens normally or routinely.... except in this DLC...

There are much better steam simulations in Railworks (2007) and Train Simulator (2013).

NB: The blower is also used in real life to direct the draught away from the cab when the firebox door is open and the train is in a tunnel or deep cutting, to prevent the fire from blowing back onto the driver and fireman.

[Zap]

The blower does not "feed an air draught onto the top of the fire". It blows steam up the chimney, this creates a vacuum in the smokebox and pulls air through from the firebox.

[Zap]

"The safety valve(s) should only open if there is a monstrously high excess of steam from a nearly empty boiler, or if the boiler is full of water and the fire is ridiculously hot (and has been so for a very long time). Emergency safety valve blowing It is not something that happens normally or routinely.... except in this DLC..."
This is utter garbage - It most certainly was routine for steam engines to blow off steam from the safety valves. I am old enough to remember hanging around my local station watching the steam trains, back in the days when all trains were steam not just a few preserved ones. Most locos blew off steam while waiting at the station.

[Sim Guide]

Originally posted by Zap:

The blower does not "feed an air draught onto the top of the fire". It blows steam up the chimney, this creates a vacuum in the smokebox and pulls air through from the firebox.

Yep. The blower (ultimately) feeds air to the fire, in the real world, making it burn more intensely,and raising the boiler pressure. In the Spirit of Steam DLC it reportedly reduces the boiler pressure, as currently modelled - which would be, in my view, utterly wrong. The wording from the BTC is:

"Its function (the blower) is to create a smokebox vacuum for the following purposes: (a) To increase the draught on the fire when the locomotive is stationary in order to raise the steam pressure; (b) To clear smoke; (c) To counteract backdraught; (d) To supplement the blast...."

Experts, eh...? You can't live with them, and you can live without them (if you are so inclined).

[Sim Guide]

Originally posted by Zap:

"The safety valve(s) should only open if there is a monstrously high excess of steam from a nearly empty boiler, or if the boiler is full of water and the fire is ridiculously hot (and has been so for a very long time). Emergency safety valve blowing It is not something that happens normally or routinely.... except in this DLC..."
This is utter garbage - It most certainly was routine for steam engines to blow off steam from the safety valves. I am old enough to remember hanging around my local station watching the steam trains, back in the days when all trains were steam not just a few preserved ones. Most locos blew off steam while waiting at the station.

If you really do enjoy seeing locomotives constantly blowing off steam because the DLC's coding has not been completed, then you should really love the Spirit of Steam DLC, because this happens 90% of the time. And because it drowns out all of the other audio, so painstakingly (but pointlessly) recorded on the Grand Central Railway, you won't be bothered by the other sounds at all, and you will be able to fully enjoy the sound of safety valves blowing off at maximum volume, nearly all the time. I do not think this is everyone's cup of tea, or particularly authentic, but DTG will no doubt be very happy that someone is enjoying themselves and constantly blowing off with this DLC...

Blowing off steam is (and was) extremely bad practice. It is to be avoided. It might well happen, maybe for a few seconds, for a loco in full steam readying for a big climb, but it is wasteful. The BTC handbook for enginemen says:

"Blowing off can be avoided by careful management of the fire and injectors. On a modern 4-6-0 locomotive with a tractive effort in the neighbourhood of 26,000 lb, there is a loss of pressure and wastage of approximately 10 gallons of water for each minute the safety valves are open."

The BTC never recommended constantly running boilers beyond their registered working pressure, because that would end up becoming quite expensive. I therefore believe that the two locos in the Spirit of Steam DLC are not prototypical. You could say that they are "utter garbage", if you were so inclined to say such things.

I would like the Spirit of Steam DLC to implement manual control of the firing (as presumably originally intended), to include coal management and water management via the injectors. I would then be able to manage the boiler pressure properly, without blowing off the safety valves. I would then be able to hear the other sounds, which are critical to immersion and enjoyment. The DLC is currently unplayable with any volume on.

[kubanskiloewe]

i like it as it is....not to complicated or oversimulated but for hardcore simers they should go more deep , yes.

[Zap]

I repeat - I was there - I saw what was happening. Any day that I went to my local station I could see (and hear) locos blowing off at their safety valves. I am sure the firemen tried to avoid it, but that was not always possible. In those days trains had to work to a timetable. Not having enough steam meant they would be unable to keep to time. This was always considered worse than wasting steam though the safety valves.
Manual control of firing in TWS2 would certainly help. Although, for some people, this might be more complicated than they want. An important part of the skill of firing is to plan ahead. Let the pressure (and water level) drop as you near the top of a hill, build up the fire before the start of a big climb etc. It was also important for a fireman to know their driver, and how they liked to drive. The driver was always considered to be the one in charge, and it was up to the fireman to adapt. The AI fireman is not very good at either, and errs on the side of too much steam, like an enthusiastic novice. In fact I don't see how an AI fireman could possibly know your driving style, and it would be very difficult for the AI to match the firing to the route and the schedule. With an AI fireman the only real alternative to the hissing noise would be constantly running out of steam.
It would have been possible for DTG to program TSW2 so that no loco ever blows off at the safety valves, or runs out steam. I am sure many people would prefer this, but it would not be accurate to real life.

[Pizzaguy]

Originally posted by Zap:

I repeat - I was there - I saw what was happening. Any day that I went to my local station I could see (and hear) locos blowing off at their safety valves. I am sure the firemen tried to avoid it, but that was not always possible. In those days trains had to work to a timetable. Not having enough steam meant they would be unable to keep to time. This was always considered worse than wasting steam though the safety valves.
Manual control of firing in TWS2 would certainly help. Although, for some people, this might be more complicated than they want. An important part of the skill of firing is to plan ahead. Let the pressure (and water level) drop as you near the top of a hill, build up the fire before the start of a big climb etc. It was also important for a fireman to know their driver, and how they liked to drive. The driver was always considered to be the one in charge, and it was up to the fireman to adapt. The AI fireman is not very good at either, and errs on the side of too much steam, like an enthusiastic novice. In fact I don't see how an AI fireman could possibly know your driving style, and it would be very difficult for the AI to match the firing to the route and the schedule. With an AI fireman the only real alternative to the hissing noise would be constantly running out of steam.
It would have been possible for DTG to program TSW2 so that no loco ever blows off at the safety valves, or runs out steam. I am sure many people would prefer this, but it would not be accurate to real life.

this is perfect. it brings me back to the train simulator days where I would intentionally drain the water supply low to use less steam and then turn on the injectors when approaching a station, sometimes I could completely avoid wasting steam if the timing is right, but that wasn't always possible. Reminds me of a story I heard of a guy who liked to run his steam locomotives low on water in the day because "high water robbed the engine of steam" or something along those lines. I am not sure if that is because of something to do with thermodynamics or if they used the same method I like to use. Anyways, supposedly they went around a corner and the water sloshed around and exposed the crown sheet, and if you know what that is, you know what happens next. anyways, I cant say if the story is true, but its a neat little story anyhow. I would really like to see some sort of mechanism in the game where you could control fire and water, and set an automatic cap to a certain level, that would allow you to control the level of coal and water without fiddling with it too much, and let the driver do the driving and the fireman do the firing more effectively.

[Sim Guide]

Originally posted by Zap:

I repeat - I was there - I saw what was happening. Any day that I went to my local station I could see (and hear) locos blowing off at their safety valves. I am sure the firemen tried to avoid it, but that was not always possible. In those days trains had to work to a timetable. Not having enough steam meant they would be unable to keep to time. This was always considered worse than wasting steam though the safety valves.
Manual control of firing in TWS2 would certainly help. Although, for some people, this might be more complicated than they want. An important part of the skill of firing is to plan ahead. Let the pressure (and water level) drop as you near the top of a hill, build up the fire before the start of a big climb etc. It was also important for a fireman to know their driver, and how they liked to drive. The driver was always considered to be the one in charge, and it was up to the fireman to adapt. The AI fireman is not very good at either, and errs on the side of too much steam, like an enthusiastic novice. In fact I don't see how an AI fireman could possibly know your driving style, and it would be very difficult for the AI to match the firing to the route and the schedule. With an AI fireman the only real alternative to the hissing noise would be constantly running out of steam.
It would have been possible for DTG to program TSW2 so that no loco ever blows off at the safety valves, or runs out steam. I am sure many people would prefer this, but it would not be accurate to real life.

Yep. I agree with you that if you run a steam engine's boiler to the point where the safety valves blow off steam, that they will blow off steam. Briefly. Relatively rarely. Some drivers will let-off steam as a precaution, before the full safety valve goes off (because it is really not good to let this happen).

And then the pressure will drop and the blowing off will stop. And the fireman will stop maniacally adding coal and would add water with the injectors to manage the pressure.... but in TSW2's Spirit of Steam, the following things happen:

- each service starts with the steam blowing off with boiler at full pressure, so you get no choice at the start;
- the boiler pressure does not drop in reaction to the safety valves blowing off, so they continue at full bast;
- the fireman continues to add coal, and you cannot stop this;
- if you are moving light engine around a yard then not enough steam will be taken to shut down the safety valves;
- if you achieve line-speed then not enough steam will be taken and the safety valves will blow off whenever you are not applying full power;
- if you are coasting then not enough steam will be taken to shut down the safety valves;
- if you come to a stop at the top of a hill and have little need for power on the descent, then the fireman will respond by maniacally fuelling the fire even more; and....,,
- in the rescue scenario, the failed steam locomotive also has a crazy fireman piling on coal and blowing off steam through the safety valves for 100% of the journey.

None of the above is normal or routine, or always happening, in real life. It isn't normal to grossly mismanage the boiler pressure and then when you are warned about it, to continue to mismanage the boiler pressure - even when most of the time you do not need high boiler pressure. The locos have not been modelled like this for creative reasons (I hope....) - the DLC is just broken and incomplete.

The blowing off of steam is so disruptive in the game that even when DTG previewed the DLC in their livestream, they turned the volume down and kept the camera as far away from the engine as possible - it was that painful for them to work with it for even just a couple of hours. They could barely showcase the sounds they recorded from the 8F because they were continuously drowned out by the safety valves.

But if you do like the sound of the safety valves above all else, then this is all obviously perfect. I am just not one of those people.

NB: I have no problem with automatic settings for steam engine firing, but when they are enabled the auto-fireman should act vaguely realistically, so that some of the other audio can be heard. This is not impossible or difficult to do. DTG just has not got around to it yet - like calibrating the improbable timetable, or doing any effective QA. We will have to wait, probably until about the end of next year (2023, as I write this), before Spirit of Steam is ready to be released for sale as a working product.

[Zap]

I have many times seen steam locos blowing off steam. There is nothing you can say that will ever convince me that the locos I saw blowing steam through their safety valves were not, in fact, blowing steam through their safety valves. All you are doing is angering me with your repeated insistence that I am lying, and convincing me that you have no idea what you are talking about. As well as observing locos blowing steam through their safety valves, I also have several books about railways. Many of the photographs in these books show locos blowing off steam. I even have one with a photo of a Royal Scot loco at Edgehill. It has just climbed up from Lime Street, and according to the caption, is at the head of a London bound express. Guess what? It is blowing off steam from the safety valves.

I am not saying that the AI fireman is perfect - it clearly is not. To take your points in order:-
"- each service starts with the steam blowing off with boiler at full pressure, so you get no choice at the start;" Well it would, you have to have the blower on, at least a little, for the reasons you stated yourself. There is a limit to how much steam you can use up with the injectors. If you put too much water in the boiler, then when you open the regulator it will "prime". You will get water going through the cylinders instead of steam. At best you will spray boiling water over the platform, at worst a cylinder could explode and kill someone. Much better to let a little steam out through the safety valves.

"- the boiler pressure does not drop in reaction to the safety valves blowing off, so they continue at full bast;" I agree with this one. If the loco is standing (or coasting), then the steam generation rate should be very low. The rate the steam escapes through safety valves should be much higher, so the pressure should go down. In fact safety valves used to lift in two stages. The first stage was a soft blow, known as a "White Feather". The second stage was a full on blow. TSW2 does not include the "White Feather" stage, it just goes straight to the full blow.

"- the fireman continues to add coal, and you cannot stop this;" I am not sure about this. TSW2 does not tell you how much coal is in the firebox. Although there is an animation of the fireman appearing to shovel, it is not clear how much (if any) coal he is actually shovelling, or indeed why? There does not appear to any coal on his shovel. I would agree that this area needs a lot of work.

"- if you are moving light engine around a yard then not enough steam will be taken to shut down the safety valves;" I think I covered this above. The safety valves should cut in, until the pressure goes down, and then cut out.

"- if you achieve line-speed then not enough steam will be taken and the safety valves will blow off whenever you are not applying full power;" You can control this with the cut-off and the regulator. The loco will create more steam with a long cut-off and low regulator than with a short cut-off and full regulator. Try reducing the cut-off as you pick up speed. The Jubilee should be quite happy at about 15% cut-off, or perhaps a bit less, if you are going fast enough. Of course you should always start in full gear (75%) and only reduce the cut-off once you are moving.

"- if you are coasting then not enough steam will be taken to shut down the safety valves;" I think this has already been covered.

"- if you come to a stop at the top of a hill and have little need for power on the descent, then the fireman will respond by maniacally fuelling the fire even more; and....,," I can't say I have noticed the fireman shovelling any faster when you go downhill. I think your point is that he does not go any slower. I said in a previous post that the AI is not aware of the route or schedule, so it cannot predict how much steam you are gong to need in future. It would be nice if it could, but I don't see how it can be done. At best the AI will react to what you have just done, rather than what you are about to do.

"- in the rescue scenario, the failed steam locomotive also has a crazy fireman piling on coal and blowing off steam through the safety valves for 100% of the journey." I have not tried this one yet.