Atomic Systems

I've noticed in quite a few scenarios that the safety-valves lift at pressures way below the maximum boiler pressure and that they stay lifted for considerable period of time, causing drops of 20-30psi. Valves lifting at, say, 160psi on a boiler pressed to 220psi is clearly unrealistic so it would seem that the operation of the valves is not linked to the boiler pressure in TS012 and can be used to make a scenario more difficult to play. Have I got this right? It drives me round the bend when I try to bring up the boiler pressure by restricting the steam consumption only to have the valves lift so far before they technically ought to and undo my work.

Keith

I'm guessing this will be set in one of the simuation file - it is either set too low or as you say there is some disconnect.

B

That's my guess, too. Being a new user who hasn't done any editing yet, though, I don't know where to start or what to do with which editor or tool. I'm hoping that someone will come along and hold my hand!

Keith

It's set in the simulation.bin file in the loco's simulation folder (filename may differ). Here's the relavant section of the file (Black5 Engine Simulation.bin) for the default Black 5:
Note that there are two safety valves here, one opens at a lower pressure than the other and has a lower steam flow rate (SteamUsage) than the other.

Andy L

Andy, thank you for this. Which editor do I need to use to work with this file? And another couple of questions, if you wouldn't mind:
1) If the same type of loco behaves differently in different scenarios does that mean there will be another file for that scenario that overrides the default one?
2) If so, where would this file probably be situated and would it have a similar format?

The fact that the two valves have slightly-different lifting points doesn't surprise me as it's standard practice on all boilers. In the seventies I was an apprentice at a firm that built industrial boilers (up to 550MW for power-stations) and, on them, reheater safeties lifted first, then the superheater safeties and finally the main drum. If the last ones lifted then something was seriously adrift and I only ever saw that happen once. Having this "cascade" arrangement means that the wasted water and energy is minimised and the crew have a chance to get things back under control but the second one is there to make sure that the pressure can always be controlled even when steam production is very high at the time demand is reduced.

Keith

You can have any number of safety valves, which is useful for things like GWR engines which had progressive ones rather than pop valves. And you're totally wrong, it is linked to boiler pressure, but certain engines may have the wrong pressure set in the valves ( like the Falmouth Pannier ), or perhaps they're a different subversion of the engine you're thinking of with a different pressure.

Probably helps to say what you're trying to drive.

Kariban, I can think of two examples off the cuff: the 5MT in Keeping Up With The Diesels and the 4MTT in Ferryhill Fiddle.

Can I take it that many performance parameters for any loco can be set in this way, such as the relationship between the steam production and consumption versus the combination of regulator and reverser? I can't remember the scenario name but there's one on Bath-Templecombe route where you start with a 7F banking. In the early stages the loco you're driving won't steam for love nor money and it's impossible to get the pressure above 180psi, making the drag over the steeper banks an absolute pain but as soon as the 7F is uncoupled the pressure jumps to 220psi, it will subsequently steam on a candle and you can't make the pressure drop no matter what you do. It doesn't make the scenario unplayable but it is a bit bizarre!

Keith