RSC 2-8-0 CONSOLIDATION

[BNSFdude]

50 sounds good. When can we expect a beta. You know what I mean as we I assume.

[buzz456]

"A very general rule of thumb with steam locos is the (theoretical) max speed is roughly 1.2 times the driver diameter in inches so a loco with 50 inch drivers should max out at about 60 MPH. One with 80 inch drivers around 96 MPH. Obviously there are exceptions and other factors that apply. One important one is the amount of weight in reciprocating motion (side rods, connecting rods, cylinders, etc). The more drivers the more weight so a 4-4-2 isn't as hard on the track then a 4-8-4 at the same speed."

This is from a blog when I was poking around.

[mrennie]

"A very general rule of thumb with steam locos is the (theoretical) max speed is roughly 1.2 times the driver diameter in inches so a loco with 50 inch drivers should max out at about 60 MPH. One with 80 inch drivers around 96 MPH. Obviously there are exceptions and other factors that apply. One important one is the amount of weight in reciprocating motion (side rods, connecting rods, cylinders, etc). The more drivers the more weight so a 4-4-2 isn't as hard on the track then a 4-8-4 at the same speed."

This is from a blog when I was poking around.

I'm not too sure about the last sentence. One of the advantages of more axles, apart from added traction, is that it distributes the weight over more spots on the rails. The disadvantage is that to get more axles along a given length of frame, the wheels have to be smaller, which means less speed (the wheel circumference is less so the wheels travel a shorter distance on each stroke.

I found another fantastic document, in PDF format, written by Llewellyn V. Ludy M.E., Professor of Experimental Engineering, Purdue University, American Society of Mechanical Engineers, called "A Practical Treatise on Locomotive Boiler and Engine Design, Construction, and Operation", for the American Technical Society, Chicago, in 1920 (the year the real Lima Consolidation was built). 177 pages full of extremely useful material.

One interesting bit is on page 128. It's a formula for the tractive effort.

T = (0.85 .p.d.d.L) / D

where

T = the tractive force in pounds
d = diameter of cylinders in inches (24" for the Consolidation)
L = stroke of the piston in inches (20" for the Consolidation)
D = diameter of the driving wheels in inches, including the tires (the Consolidations wheels are 40" in diameter, but then you have to add another 4" to allow for freshly applied 2" thickness tires)
p = boiler pressure in psi

It says that 0.85 relates to the mean effective pressure on the piston in psi.

There's a more complex formula for 2-cylinder compound locos (which have a low and a high pressure cylinder).

There's even a (very complex, but apparently very accurate) formula to calculate T, the number of tons including engine, which can be hauled over a grade, for a given starting velocity at the start of the grade and velocity at the top of the grade, taking into account the same parameters as before, as well as the tonnage of train, the grade and length of grade, etc. I'll have to calculate it for the Consolidation and then do some test runs to see if I can match it to T. Interestingly, it says that for empty cars, you have to add 40% to the friction with respect to loaded cars. i think might be because for the same tonnage, you'd need more empty cars than loaded cars, so the same tonnage of empty cars would indeed have greater friction (more wheels. more cars facing the direction of travel).

I put in the numbers for the Consolidation, and it comes out that if I begin a 1.8% grade at 20MPH, after 1 mile, hauling 885 tons of loaded cars, it should have slowed to 10MPH, assuming the locomotive is run as efficiently as possible. I'll set up a test to see.

[mrennie]

50 sounds good. When can we expect a beta. You know what I mean as we I assume.

Matt said something about putting a beta on Steam. I didn't really know what exactly he meant by that. Does Steam have some kind of private area for beta testers? I'm new to this.

I'm finishing the sound package now. I'm very, very pleased with it .... the chuffs are in stereo and the bass sends a tingle down my spine (in fact, I decided to reduce it a bit). I think it sounds just like in the recordings I've heard. Once you turn on the generator and compressor too, the sound is incredible.

[BNSFdude]

Yeah, beta team has private distribution. I'm excited, I may do a review on this guy when it comes out.

[mrennie]

Yeah, beta team has private distribution. I'm excited, I may do a review on this guy when it comes out.

I look forward to it!

[mrennie]

I haven't done the scenarios or manual yet (and yes, it needs one). The idea is to leave it with the beta testers over the holidays, so that I'll have feedback when I return in the second week of January. That should leave enough time to give it a thorough workout. I haven't had time to test run it as much as I would have liked, so there might be one or two buglets left, but hopefully nothing serious.

I'll do an instruction scenario, to go through the start-up procedure (nothing difficult, it's just that there are a few extra things to do compared to the usual steamers, mostly turning on the various steam supplies from the turret to the equipment, which you only need to do once). Plus you have to make sure to work the injectors properly (or you'll just get steam or water coming out of the overflow pipes). And then there are the "special" keys for some special things I added.

[mrennie]

I did the calculations for the grade test. It starts at the beginning of the 1.1% grade heading out of Altoona, at an initial 20MPH. In theory, at 1 mile further up, with a 35 car consist, on a dry day, the train should slow to 10MPH. Well, I crossed the 1 mile point at 10MPH

What this shows too is that nobody should expect to get over the summit with a 35 car consist hauled by a single Consolidation! It's not a Big Boy after all.

[bpetit]

So the introduction will be fine with auto fireman?

[mrennie]

So the introduction will be fine with auto fireman?

So far, all the testing I've done has been in expert mode. I'll have to do some tests in other modes and see what happens. I'm not sure how simple mode will handle my firebox butterfly door mechanism or the pick-up water injectors. I remember a while back doing a test run with a double-header over Sherman Hill. I was doing fine in the lead loco, but the scenario came to an abrupt halt when the stupid fireman in the loco behind me ran out of water. I still had plenty.

[CaseyRhodes]

Man its really kind of a pain to have to fire and run at the same time on this game.... Hopefully automatic fireman will be available on it haha,

[mrennie]

Man its really kind of a pain to have to fire and run at the same time on this game.... Hopefully automatic fireman will be available on it haha,

I've added the simple mode controls too. Now I'll see if the automatic fireman is able to do his job properly. EDIT: Yep, he works fine

By the way, I still have a nagging doubt. To apply the brakes, is the handle moved from left to right (that's the way I've modelled it at the moment) or from right to left?

[BNSFdude]

Correct, left to rightto apply. Should have a Quick Charge, Release, Hold, Lap, Service (apply) and Emergency.
http://www.sdrm.org/faqs/brakes/control/6stand.html

[mrennie]

Correct, left to rightto apply. Should have a Quick Charge, Release, Hold, Lap, Service (apply) and Emergency.
http://www.sdrm.org/faqs/brakes/control/6stand.html

Thanks! So they got it backwards in the K4. They put 100% on the left, 0% on the right.

I'm still waiting for the crew figures from the K4, but if I don't get them by tonight, I'll upload the package anyway (to the RSC ftp). I can always add the crew later.

[mrennie]

There's something strange happening. I put the notch identifiers, as you said, into the control values part of the engine blueprint (interior irregular notched lever), but the names that appear in the F5 display when I move the handle are different, and go as follows: direct > release > direct > emergency. I have no idea why. I didn't write "direct" anywhere in the blueprint.