Boiler explosion under normal conditions

[TheFluffyGoose]

Happened a few days ago on an old now deleted realistic difficulty profile. Was going up a hill. Water was slightly below the halfway point on the gauge, temperature was around 800 inside of the furnace, steam pressure was around a 9, and I had the regulator around 60-70%. The rest is history. Any clues as to why so I can avoid it the next time I use a steam engine?

[pitty3878]

S060 or s282?
The gauge glass on the 060 is not 100% accurate.
Usually the best idea IMO is to run the 060 at 90% water.
The 282 you can run pretty low. About 1/4 of the gauge glass.

But up hills try and keep the glasses at 75% as you flatten out off the grade it'll drop significantly.

Hope this helps.

[TheFluffyGoose]

Originally posted by pitty3878:

S060 or s282?
The gauge glass on the 060 is not 100% accurate.
Usually the best idea IMO is to run the 060 at 90% water.
The 282 you can run pretty low. About 1/4 of the gauge glass.

But up hills try and keep the glasses at 75% as you flatten out off the grade it'll drop significantly.

Hope this helps.

S282, sorry for not clarifying. Water gauge was at about 45%.

[schutt]

I sometimes wish the game would have an build in recording feature so you can watch replays of your drives. What normally happens: the grade changes to a descent, then 50% water becomes not enough water ( water glass empty) crown sheet heats up and then a new grade comes or heavy braking, slushing the water back over the crown sheet.

For example the grade going up the loop up to the mountain in the northeast has a short descent in between, right before the switch that branches off to the military complex.

[ling.speed]

9 bar is awfully low, you say now deleted realistic profile, could it be an old profile, before steam startup changes? around 9 bar is where startup boost kicks in, so the pressure could have dropped to a point where that went off, and overheated something.

On steepest inclines having water below middle means level water line is well below "zero" and into overheat poping sound. It still probably should not blow up, but any small mistake from there could lead to explosion.

Unfortunately for now the game explodes the tank whenever something catastrophic happens inside it, it can be from overpressure but could also be from insides deforming at lower pressures, so even if you saw 9 bar just before explosion the thing still could have been overheating from not enough water.
ps: if the explosion occured exactly at 45% water level, any incline, its more likely a bug or rare mechanic, like maybe loco was damaged?.



As for tips for Steamers:
The regulator position does not matter much, its mostly for keeping chest pressure below tank pressure during initial roll, as soon as you are driving normally there is little reason not to flip it between 100% and 0% only. High regulator position wont affect boiler damage. How much steam (power) is used should be controlled by cutout.

Try to keep much higher tank pressure, 12-14 bar. You can use injector to reduce pressure immediately if you shuffle too much coal. Damper can be used as well but it has delay. The higher tank pressure the more efficient steamers run.

When the water indicator shows 100% tank is still far from full, it takes ~ half more of the indicator to be close to overflow - you will see it on the non interactive valve above the indicator as water leakage. So dont be scared to fill more.



Assuming no bugs or glitches with old realism settings, what could have caused the explosioon, was ineffieicnt use of steam, and/or too high injector position that dropped the pressure to 9bar and dried up the tender water tank, which then in very short time frame can overheat the boiler (high steam consumption + no new water coming in). And also false sense of security from incline (and/or acceleration) showing more water than boiler had.

[TheFluffyGoose]

Originally posted by ling.speed:

9 bar is awfully low, you say now deleted realistic profile, could it be an old profile, before steam startup changes? around 9 bar is where startup boost kicks in, so the pressure could have dropped to a point where that went off, and overheated something.

On steepest inclines having water below middle means level water line is well below "zero" and into overheat poping sound. It still probably should not blow up, but any small mistake from there could lead to explosion.

Unfortunately for now the game explodes the tank whenever something catastrophic happens inside it, it can be from overpressure but could also be from insides deforming at lower pressures, so even if you saw 9 bar just before explosion the thing still could have been overheating from not enough water.
ps: if the explosion occured exactly at 45% water level, any incline, its more likely a bug or rare mechanic, like maybe loco was damaged?.



As for tips for Steamers:
The regulator position does not matter much, its mostly for keeping chest pressure below tank pressure during initial roll, as soon as you are driving normally there is little reason not to flip it between 100% and 0% only. High regulator position wont affect boiler damage. How much steam (power) is used should be controlled by cutout.

Try to keep much higher tank pressure, 12-14 bar. You can use injector to reduce pressure immediately if you shuffle too much coal. Damper can be used as well but it has delay. The higher tank pressure the more efficient steamers run.

When the water indicator shows 100% tank is still far from full, it takes ~ half more of the indicator to be close to overflow - you will see it on the non interactive valve above the indicator as water leakage. So dont be scared to fill more.



Assuming no bugs or glitches with old realism settings, what could have caused the explosioon, was ineffieicnt use of steam, and/or too high injector position that dropped the pressure to 9bar and dried up the tender water tank, which then in very short time frame can overheat the boiler (high steam consumption + no new water coming in). And also false sense of security from incline (and/or acceleration) showing more water than boiler had.

Thanks for this. At this point it doesn't particularly matter since I've already unlocked the slug and I'm on my way to MF to pick up the replacement DE6 parts, so realistically I don't see myself using steam engines again on this save. I still want to have this knowledge just in case the devs add a retro gamemode with steam engines only or achievements related to steam engines.

When I say "old deleted realistic profile" I mean old as in a few days old. I made the profile the same day I deleted it.

I was trying to keep the pressure up while going up the hill from SM towards FRC right after the bridge to FM...going backwards. I read the job order wrong and thought I was delivering to SM, but in fact it was for SW. Did going backwards have anything to do with it? I am not sure if the game simulates going backwards causing less radiator airflow and thus higher temps (though I suppose the steam engine doesn't have a radiator).

I've noticed the more water you let into the boiler the lower the pressure goes. I suppose my problem was not putting enough water in the boiler in the first place then trying to add more while on an incline, starting a vicious cycle of losing steam pressure causing a loss in power but needing to add more water to prevent an explosion.

Water tender was completely full, I had just refilled it. Loco was not damaged either. I think you are correct about temperature and low pressure. It was moving between 8.8-9.2 bar, and I think that in combination with a hot furnace blew it up.

As for the cutout, I was treating it like a drive selector in a diesel. I thought the regulator was the throttle. Now I know the cutout is actually the throttle.

[ling.speed]

Originally posted by TheFluffyGoose:

Thanks for this. At this point it doesn't particularly matter since I've already unlocked the slug and I'm on my way to MF to pick up the replacement DE6 parts, so realistically I don't see myself using steam engines again on this save. I still want to have this knowledge just in case the devs add a retro gamemode with steam engines only or achievements related to steam engines.

As a curiosity thing, there are handful of cases where 282 can outperform DE6, even with slug. Power wise they are the same, but steamer has no limitation on traction motor heat and has no need for gears that on DE6 can go against you during uphill pulling. With new chest simulation it might be faster too (didnt try in recent patches). Also its much, MUCH, cheaper to run.
So as long as its fun to drive it can be end game loco no problem.

Did going backwards have anything to do with it? I am not sure if the game simulates going backwards causing less radiator airflow and thus higher temps (though I suppose the steam engine doesn't have a radiator).

That is simulated thou most trains are designed to run without much dynamic airflow. In older patches it was a significant effect when pulling with 2+ locos (at least one radiator having obstructed intake) but its very small thing now.
But going backward in a steamer with little water could have been more deadly than going forward. As piping just over firebox is at the back of the tank, and would be exposed at low water levels while pulling (high steam throughput, high firebox temp). Afaik its possible to blow up just by going over top of a hill by inclination moving water around.

I've noticed the more water you let into the boiler the lower the pressure goes.

True but only because we let cold water in. Give it some coal and it will be back to 14bar. Full tank of 14bar is a heck of a battery, you can do light shunting with cold/extinguished firebox.

As for the cutout, I was treating it like a drive selector in a diesel. I thought the regulator was the throttle. Now I know the cutout is actually the throttle.

Yeah its confusing. In practice both cutout and regulator are throttles, placed in sequence.

Regulator can limit the pressure coming into cylinders, cutout decides how much of the steam goes in. Both affect the final torque that gets to the wheels.

Cutout trades efficiency for power - you could think of it being like a diesel RPM controler combined with electrical or hydraulic (slip based) transmission. Close to neutral its efficient but cant pull too much - like low RPM diesel, close to max creates good torque but very inefficiently like high RPM diesel + high slip/amperage TMs.

While regulator is a power cap device (you select max power the engine can provide). At low speeds you can have very high torque even at low regulator opening because power will be low, but as you speed up the torque drops to keep power constant. Notably it does so by making the engine less efficient (think of clogging the tailpipe rather than reducing fuel flow)