DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 7, 2006 17:24:52 GMT
One for you more senior experts, maybe. A guy on UKTS is implementing a real nice realistic cab for the MSTS 38TS. He's trying to implement a realistic brake system and I'm trying to help (I know how, but don't know exactly what we need to model). Thus, some key questions: Was it a lapped Westinghouse? Did it have partial release? What were the positions on the brake controller for (we do have a nice realistic controller with the detent positions)? Note, we can't implement the EP part as well as MSTS can't do 2 brake systems. Any and all info deeply appreciated!
Best, Jimi
|
|
Phil
In memoriam
RIP 23-Oct-2018
Posts: 9,473
|
Post by Phil on Apr 7, 2006 18:08:30 GMT
Cannot answer it fully, but Westinghouse did not have a partial release. Neither did it (or indeed do C stock etc) have self-lapping. S-L was for the EP brake only.
If MSTS only allows one system, might it be worth considering EP rather than Westinghouse since that was the everyday system??
|
|
towerman
My status is now now widower
Posts: 2,860
|
Post by towerman on Apr 7, 2006 18:43:23 GMT
On a 38TS brake controller it was 1.off and release 2.full EP application 3.lap 4.service application 5.emergency Between 1 & 2 there was the graduated application and release on the self lapper.
|
|
|
Post by CSLR on Apr 7, 2006 18:49:09 GMT
If MSTS only allows one system, might it be worth considering EP rather than Westinghouse since that was the everyday system?? But Westinghouse was MUCH more fun. If these guys can create a realistic one that would be terrific. Might it be possible to make it selectable between the two versions and to choose which system you want to use on the line? That way everyone would be happy and could make comparisons between the different types of braking system. DrJimi saidFor a Westinghouse application on 38ts, bring the brake handle sharply though all of the EP positions until it is pointing directly towards the driver. The spring lug in the handle should have passed the large projection that it has just ridden across, but be gently pressing back against it. This is the 'lap' position. The brake can now be applied with with a series of 'service applications' that slowly increases the pressure on the brake shoes. At the end of its travel, the brake handle goes into full 'emergency' - and makes a different sound. You cannot release the brakes after applying them without taking the handle right back to the common release position for Westinghouse and EP. Even then, unless enough Westinghouse has been applied at some point in the braking, the brakes will often become 'sticky' and not release properly. In practice an experienced driver would go from lap to application to lap (repeated as required) and just before the train stopped, throw the brake off completely to allow it to come gently to a stand with no bump. Then to prevent it rolling after stopping at the station he would move into a light EP position (I do not know how you can do that if you only have one brake system). If the brake was returned to a light Westinghouse after stopping (brief service application and then back into lap), there was a danger that some brakes would stick after the handle was moved to release. But, as this did not always happen, and was not intended to, I guess you could ignore it and build the brakes as they should have worked. Thus: stop the train, lap, slight Westinghouse, back to lap and hold. Move to release after the bell and drive away. Drivers always considered that a proper Westinghouse application was only achieved by slowly increasing the brake pressure. It was OK to return to lap, but the brakes should never be released until just before the train stopped. If you are going to do Westinghouse, why not a pre-38 (Standard stock) as well? Then you could have pure Westinghouse and a much more interesting compressor sound!
|
|
Phil
In memoriam
RIP 23-Oct-2018
Posts: 9,473
|
Post by Phil on Apr 7, 2006 20:43:35 GMT
Then you could have pure Westinghouse and a much more interesting compressor sound! That's my one complaint about the 38ts on BVE. They have used the reciprocating compressors sound off the 59/62s. The 38ts had rotary compressors which had a unique sound (even if they were not as successful as the reciprocators).
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 7, 2006 21:57:23 GMT
Thanks all! I of course transposed EP and Westinghouse through my post. Brain thinking one thing, fingers typing another: I meant we CAN do EP, but not Westingouse AS WELL. I thought it was self-lapping and partial release. Thanks for confirming, and the extra details!! I know how to do that in MSTS. I actually implemented a good EP + blended Rheo in my original CO/CP MSTS offering. But the blended rheo and combined controller (CTBC) prevented partial release of the EP (don't ask -- blame Kuju). I fudged it to work in the V2.3 update and improved it for the D78.
|
|
|
Post by mowat on Apr 10, 2006 10:51:30 GMT
Can I remember somone doing a 1959/62 stock cab at UKTS somtime ago. Also I think that CSLR's idea of having two one whith EP and the other whith Westinghouse is a good one, is there any chance of this?
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 11, 2006 21:38:28 GMT
One more question for the experts... On the duplex brake gauge, what color was each needle, what function did each display, what was the scale range (numeric)?
It looks like we're very close to a real 38TS cab and controls. Just need to sort the brake gauge and then do a little road testing ;D
Thanks in advance, Jimi
|
|
|
Post by CSLR on Apr 12, 2006 6:10:34 GMT
On the duplex brake gauge, what color was each needle, what function did each display, what was the scale range (numeric)? Main Line - Red Train Line - Black Main Line showed the air pressure in the air reservoir. Train Line showed the air pressure in the train line brake pipe. I am pretty sure that I have one knocking around somewhere (a duplex gauge, not a 38ts). I will try to dig it out later today and send you a photograph of the numeric display. Although I am not certain, I think that I might possibly have a set of training notes for brake operation on the 1938 stock. If so, would you like me to locate those and send you a scan?
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 13, 2006 1:31:22 GMT
Thank you sir! Duly sorted. In essence the gauge now works and looks right, with only a few small tweaks left. Regarding the training material, should you have the spare time to do so (I stress, entirely at your convenience) I welcome such material with open arms. Partly as I'm inherently interested in such things, and partly as it helps to validate the 'virtual renditions' are as good as we can make them, within the usual Kuju limitations I can PM you an email addy if that would be appropriate. Thanks again, Jimi
|
|
|
Post by trainopd78 on Apr 13, 2006 11:03:23 GMT
All LT stocks until and not including the 1967ts had self lapping EP, but no rheo hence the 2 handles. Anything one arm bandit style has a rheo. The EP on the 38ts has an infinate number of braking positions, but in practice would take forever to apply and release on a sim, so a number of notches would be better for ease of use. I do like the idea of 2 no. 1938 stocks, one with EP and the other with windyhouse brakes. I luuurve windyhouse.
|
|
|
Post by CSLR on Apr 13, 2006 12:36:28 GMT
With sufficient, umm, "incentive" a Westinghouse-only version could certainly be produced for you hard-core enthusiasts I expect to be in the vicinity of New Hampshire a little later in the year. Maybe I could line a few pints of "incentive" up on the bar.
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 13, 2006 17:40:49 GMT
...The EP on the 38ts has an infinite number of braking positions, but in practice would take forever to apply and release on a sim, so a number of notches would be better for ease of use. We can do either notched or variable. With the variable, there is a parameter that defines how much effect a single keystroke has, thus if set appropriately, you wouldn't be "holding the key down" (key repeat) to get appropriate application. Partial release would also work using the same granularity. I got to test the new cab and controls last night. It's "functional" bit needs a little tweaking. Do you folks happen to know the PSI drop on the black needle (train pipe) for the initial EP application ("Just on") and the total drop at full EP? I want to make sure we're using all the right values for the brake system. I can fine-tune the actual braking force afterwards. Red needle seems to behave itself and correctly report the res pressure. Compressor kicks-in correctly and re-charges, but I'm not sure if the values are right -- max res pressure and recharge pressure. Anyone know those also? Does a triple valve ratio apply? If so, ratio? The "incentive" comment was tongue-in-cheek BTW. I'll certainly implement a version after we get the EP working right. CSLR -- if you're indeed visiting my area I would certainly look forward to a chat over a cold one or two!
|
|
|
Post by CSLR on Apr 13, 2006 18:09:24 GMT
Do you folks happen to know the PSI drop on the black needle (train pipe) for the initial EP application... I am pretty sure that would be dependent on the amount of brake that was applied. I am not 100% certain on this because, at times when the brake needs to be applied, the motorman is usually looking out of the window rather than at the brake gauge. If full EP needs to be applied, the motorman should definitely be looking out of the window! I have a vague recollection that at full EP application, the needle would flicker as the blow-out valves were actuated - can anyone else remember? And do not forget the mercury retarders. I should know these off the top of my head. I have figures in mind, but want to check my notes. Sounds like I might have to invest in a smaller number of pints than I thought
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 13, 2006 18:49:11 GMT
Understood and agreed re "looking out of the window", however given the MSTS cab display the gauge will be in your peripheral vision and I'd like it to at least reflect expected operation. Besides, there's always a "rivet counter" somewhere, ready to pounce on inaccuracies ;D Maybe when I get it working reasonably I'll take a quick FRAPS video, so you folks can see if the operation "looks right". Constructive criticism is always welcome, and I've had my share with the route and various trains, to the betterment of both. PP was always good at it ;D
Me: How's it look? PP: I dont see too much wrong with it. (pause) Mind you, I haven't looked closely yet.
|
|
|
Post by CSLR on Apr 13, 2006 19:14:35 GMT
Understood and agreed re "looking out of the window", however given the MSTS cab display the gauge will be in your peripheral vision and I'd like it to at least reflect expected operation. Besides, there's always a "rivet counter" somewhere, ready to pounce on inaccuracies ;D The 'looking out of the window' comment was intended more as an excuse for all those who have driven a 1938 stock and are keeping quiet because they did not look at the gauge at that particular moment. Braking was not a time when you really needed to refer to it. Motormen will tell you that driving is a 'seat of the pants job'. When the train does not feel right, or something obviously goes wrong, that is when you check the gauges. Also, after a Westinghouse application, it was common practice to look at the duplex gauge to make sure that everything was recharged and that there was a difference between the two needles. This did not really apply when EP was being used. I agree with you Doc. It does have to be correct. Stick at it until you get the right answers. Surely I am not the only person here who remembers 38ts? It was not withdrawn all that long ago.
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 17, 2006 22:36:35 GMT
Thanks again CSLR. I now have it all functioning (except graduated release due to yet another "undiscovered feature" courtesy of Kuju : . Values are currently: Main Res max = 110psi. Recharge at 90psi (may be low but functions). Train pipe max (nominal) 80psi. Triple valve ratio 2.5. Brake cyl pressure for max brake = 57psi. So the train pipe drop and cyl pressure rise to meet at 57psi (drop of 22.8 in the train pipe multiplied by the TP valve ratio). Seems to work fine and the needles do the right things. I'm now fine-tuning the brake force for the differing DM and Trailer weights. If anyone knows any of those values to be wrong, please let me know. I've now (finally) sussed all the relevant MSTS parameters and their relationships and can adjust as needed. There are a few details left like the compressor charge rate, apply/release rates, etc. that will also be tweaked as I test it and learn more. Sadly, it does appear that the Kuju implementation of graduated release may be totally broken, but I'm still plugging away at it... Best, Jimi
|
|
|
Post by CSLR on Apr 17, 2006 22:54:05 GMT
My training notes show optimum Main Line pressure as 85 lbs/sq in. Train Line as 65 lb/sq in. Compressor governor cuts in at 70-75 lbs/sq in cuts out at 85/90lbs sq in.
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 17, 2006 23:02:23 GMT
Wow - lower than I'd expected, as I thought 110 was a UK standard (vs. 140 in USA). OK, from those figures I can calculate the cyl pressure for max brake (= train line drop times TV ratio). Thank you sir! I'll plug in those numbers and see if I hear any hissing... ;D
Best, Jimi (off the re-plumb the brake system)
|
|
|
Post by CSLR on Apr 17, 2006 23:09:10 GMT
Definitely not 110. I hope that you have not damaged anything at that pressure! I am glad that I checked the notes before I gave you the figures. My memory was 5 lbs out on the Train Line.
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 17, 2006 23:16:32 GMT
A quick plot with Excel suggests a train line drop of 18psi, yielding 45psi at the brake cyl (2.5 TV ratio) and leaving 47psi in the train line. So full service (EP) would be a train line drop of 65 to 47. Ring any bells, or am I totaly out to lunch?
|
|
|
Post by CSLR on Apr 17, 2006 23:19:19 GMT
Brake cylinder pressure cannot exceed the maximum EP valve setting of 55 lbs/sq in.
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 17, 2006 23:38:58 GMT
Brake cylinder pressure cannot exceed the maximum EP valve setting of 55 lbs/sq in. Right - if I understand the operation correctly, with a TV ratio of 2.5 the brake cyl balances with the train line at (near enough) 45psi. Here's a screenshot with the recent numbers implemented. Brake obviously Off/release. Gauge reads 0-140 in 20psi increments. Does it look "right"? (Ignore the blue needle - it's only there so I can monitor brake cyl pressure vs. decel rates). Nice cab, huh? A tallented guy named Darren gets all the credit. I'm just tweaking the physics. BTW - did the sequence light (right above the speedo) get lit when in full parallel motoring? if so, I can implement that feature. If not, please advise what it should do and I'll try and replicate. /Jimi
|
|
solidbond
Staff Emeritus
'Give me 118 reasons for an Audible Warning on a C Stock'
Posts: 1,215
|
Post by solidbond on Apr 18, 2006 6:55:57 GMT
When I was at White City we were told the brake cylinder to train line pipe was a ration of 4:1, so the equalising point was 52 psi - ie 13psi drop from 65psi. 13 x 4 = 52 psi in the brake cylinders. However, there was always the extra in the bowl of the triple valve, which could give an extra 3psi in emergency only, thereby giving the 55psi maximum ;D (see - I do remember something from White City ;D ;D)
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 18, 2006 7:25:50 GMT
BTW - did the sequence light (right above the speedo) get lit when in full parallel motoring? if so, I can implement that feature. If not, please advise what it should do and I'll try and replicate. /Jimi Well, if its any help, that light shows whether the traction current is on or off in BVE 4. (It's lit when TC is on) Joe
|
|
|
Post by agoodcuppa on Apr 18, 2006 9:02:40 GMT
Nice cab, huh? A tallented guy named Darren gets all the credit. I'm just tweaking the physics. Well done Darren. Speedo, what speedo? IIRC there isn't one in a 38 stock.
|
|
|
Post by CSLR on Apr 18, 2006 10:31:02 GMT
When I was at White City we were told the brake cylinder to train line pipe was a ration of 4:1, so the equalising point was 52 psi - ie 13psi drop from 65psi. 13 x 4 = 52 psi in the brake cylinders. However, there was always the extra in the bowl of the triple valve, which could give an extra 3psi in emergency only, thereby giving the 55psi maximum ;D (see - I do remember something from White City ;D ;D) This is the post that I have been waiting for! 4:1 rings a bell with me; I just could not find it in any of my notes. All the other figures now seem to fall into place. Thank you solidbond for the mental jolt.
|
|
|
Post by CSLR on Apr 18, 2006 10:38:40 GMT
Speedo, what speedo? IIRC there isn't one in a 38 stock. Pretty much correct. 1938 stock seemed to operate for much of its life with the speedos covered over with a black blanking plate, while a few units had installed speedos that did not work. It was always claimed that if anyone was sent up the road for failing to observe a speed restriction, the lack of speedo could be used as a defence, within reason.
|
|
|
Post by CSLR on Apr 18, 2006 11:03:50 GMT
Well, if its any help, that light shows whether the traction current is on or off in BVE 4. (It's lit when TC is on) One of the lights indicates that the motor generators are working. Because this goes out when the MGs loose current, it is often mistaken for a traction current light. It is probably best not to quote the BVE version as there are a few mistakes in it that should not be copied. For example, when an emergency brake application is made, the brake handle is actually going into either Westinghouse lap or service application (it is not easy to see which it is). It is certainly not the emergency position which is further round against the end stop that you can see.
|
|
DrJimi
Virtual District Line construction engineer and arborist
Posts: 365
|
Post by DrJimi on Apr 18, 2006 13:49:51 GMT
Major thanks to all of you - esp to SB for the 4:1 clue. As CSLR noted, it all falls into place with that clue. I'll implement those final numbers this evening. From other sources I also believe the blue light was "MGs on", and am told the lower one was the "sequence light". Exactly what sequence (related to motoring) I am not clear. I may simply light it when parallel is selected. Re the speedo - yes known and agreed. However, this is MSTS and if it didn't have a speedo then the unwashed masses would put up the "F5" digital HUD display -- which is even more unrealistic. We could, of course, reduce the speedo accuracy... ;D One related question -- what, if any, are the key differences between what we have here and a 59TS (cab/controls)? Not hard to guess why I'm asking... Thanks, Jimi
|
|