Details of steam loco steam effects

[scefhwil]

I'm currently working on some new particle effects but need some help on the nature of what actually happens in the real world. Can those in the know please enlighten me regarding the steam effects that can be seen in the following video.

http://www.youtube.com/watch?v=GbTlP2gB1Os

As the loco draws level with the camara a number of steam effects can be seem. I have these questions:-

1. Is the main continuous cloud of steam blowing out infront of the loco due to the cylinder cocks being open?
2. Coming out from the front and back faces of the cylinder visible are faint whiffs of steam. These appear to coincide with the stroke of the piston. Are these leaks or are they from valves of some type? If valves what controls them?
3. There appear to be two safety valve cylinders above the firebox. The one furthest from the cab appears to be open, is that correct? Does the second one go off at the same time as the first one? I presume the stream of steam from the second valve would be much more fierce as it releases a higher volume of steam. Is this correct?
4. What is the cause of the trail of steam coming out from between the loco and tender at rail level? Does this pipe also not eject water on occasions?

Thanks for your help.

Stuart

[emrhd01]

Hi Stuart,

This is my explanation of what you are seeing:

1. Yes this is the steam escaping from the Cylinder Drain cocks (on EACH cylinder) and will cease when they are shut. The Drain cocks are used to drain water out of the cylinders after a Loco has been standing (Water is not compressable and if left in the cylinders can blow off the cylinder heads if not drained away).

2. The steam you see here is escaping from the piston's gland packing in each forward and backward stroke of the piston. It would not be seen on a freshly renovated Loco when the packing is tight, but will gradually get worse as the packing begins to wear as the Loco gets worn out.

3. Yes two safety valves (some have four) one usually lifts slightly before the other (depends on how the pressures were set and who set them ) and yes the second often lifts at a slightly higher steam pressure than the first due to the mechanical mechanism of the Safety Valve (i.e. a Spring and no two springs act exactly the same).

4. This steam is escaping from an Injector (that's used to replace water into the Boiler), it is seen escaping from the Injector overflow pipe usually due to the Steam valve to the Injector not shutting properly, without going too deeply into how the Injector works.

Hope that helps.

[92212]

Same as above really. Just wanted to say all the best with your efforts. It would be great to see some new steam effects!!

Matt(92212)

[scefhwil]

Rob,

Thanks for the detailed, and clear, reply. Just to clarify a few points...

1. Cylinder drain cocks - opened/closed by pressing the C key?
2. These leaks will occur at all speeds?
4. Can you describe how these emissions would vary with pressing of the various keys, I, K, O & L?

Cheers

Stuart

[emrhd01]

Hi again,

1. Yes that's right the Drain cocks are opened and closed with the C key (or operating the 'lever' in some Loco cabs )

2. Yes right again, steam will leak at all speeds (have a look at one of Kevin Martin's (kevmt) excellent models, he displays it very well)

4. Very minimal amount of steam leakage (from below the cab) when the Injectors are closed (keys I & O) and slightly more leakage when the Injectors are in use (keys K & L).

If you have any further questions please ask, glad to assist.

[scefhwil]

Excellant Rob, thanks. I have plenty to try out now, but no doubt will have some more questions soon.

Cheers,

Stuart

[scefhwil]

Ok, a couple more queries.

1. If a loco is stationary, brakes on, reverser at 0, and the cylinder cocks are opened, nothing should happens, correct? Doesn't it need the regulator to be open as well to create the steam (and sound) effect?
2. Sanders. The default Black 5 has a steam looking emission from the end of the sanding pipes (at just above rail level) when the sanders are open. Aren't sanders just gravity devices, or do some loco's have them steam powered?
3. Also, should all the sanders work at once, or do they work dependant on the direction the loco is travelling (hence why the default Black 5 has some on either side of some of the driving wheels)?

Cheers

Stuart

[Rfairlie]

1. Correct no steam will come out drain cocks unless the regulator is open and the drain cocks are open. It doesn't matter if the loco is moving or not. The same applies to the leaks from the piston glands.

2.Sanders can be gravity, steam or air powered. A Black 5 has steam sanders which is the effect you see on the default one.

3.Only the sanders for the direction of travel (i.e. the ones in front of the wheel) should operate.

Tim

[scefhwil]

Thanks for those answers Tim.

Are there any rules of thumb as to which locos have which type of sander? ie region, era, or designer maybe?

Also, on a real loco how is the correct set of sanders selected? Are there two levers? Or is it mechanically set by linkage to the reverser, or something?

Finally, I've never seem steam sanders in operation. Is the default effect very realistic?

Cheers

Stuart

[Rfairlie]

The steam sander became popular in the 1890's particularly on large single wheeled locos so i suppose anything after that could carry them. Most large mainline locos would have them and things like the BR standards all have them. The thing to look for on the loco is 2 pipes coming down in front of the wheel like this one is the steam and one is the sand. Gravity sanders only have 1 pipe.

They are operated by a valve that moves 90 degrees each way from a vertical off position. 90 degrees to the left operates the front sanders and 90 degrees to right operates the rear or vice versa. Its the valve with the wooden handle in this photo http://www.fraserker.com/winson/britann ... t%2001.jpg

I can't comment on the railworks effect as i don't have a copy but will try and find a video of the real thing for you.

Tim

[scefhwil]

About time I posted an update on this.

Work has progressed well (I think anyway) albeit rather slowly. But then I did get sidetracked once I realised I could also script timed and random effects for AI loco's as well, ie one script for each loco that will give different effects for Player, Driven AI (ie ones with a driver icon) and Static AI (ones without a driver icon). I also downed tools for a few weeks before the last railworks update, just incase they did all these things anyway!

Player effects so far are:-



Whistle (needs some further work to get better timing with whilste sound), cylinder cocks (when regulator and CC valves are both open), safety valves both, going off at the required pressures), injectors (simply a case of steam if they (live and exhaust are opened) and varying chimney smoke/steam colour (needs some further work).

AI effects so far are:-

Fours levels of steam darkness, set at random (3 levels shown in the picture), random whistle and cylinder cocks going off on pulling away from stationary (with random length), saftey valve going off randomly on the loco coming to a halt. These only apply to Driven AI (ie with a driver icon). Static AI (ie with no driver icon) have no effects.



In this screenshot the train of wagons is a Driven AI (pulling away after stopping), the loco facing away is the Player, the next two locos are Driven AI (but with no destination so they won't move) and the far two locos are Static AI.

I probably will want some beta testers in a few weeks time.

Stuart

[emrhd01]

Stuart,

I can say only one thing.

You are a "Genius".

The effects you have created for RW Steam Loco's is exactly what the Steam Loco fans have wanted from Day 1 of Rail Simulator release.

RSC have begun to implement a few additional effects (i.e. Whistle & Cylinder . escaping steam) to a few of their products, but the 'AI' effects you have managed to implement, Safety Valve lifting when coming to halt and Random Whistling are something else.

I watch your progress with "baited" breath and wish you all the success that you truly deserve for your efforts with RW Steam loco's and I believe you will have no problem finding Beta testers.

Can't wait for your next progress Posting.

Very well done and for sharing your efforts with us.

[exshunter]

Stuart, you have done a super job, well done that man. The effects look fantastic. 100% in agreement with Robs post above

[plewsy2105]

one thing i will say is that all steam crews try to prevent the safety valves from lifting when they come to a halt because when the safety valves are lifting you are wasting water coal and the firemans hard work there for all crews try to stop them from lifting when on a run the safety valves are one thing i belive that if made to work correctly would make a big difference to railworks. on one engine i work on the first safety valve lifts at 165psi and the second one at 170psi.

plewsy2105

[karma99]

As already said, fantastic work mate.
If I ever find the time to finish the Q1 I was planning to spend some time on getting some nice steam/smoke effects, it looks like you're setting the benchmark to aspire to. Great stuff