shortliner Posted December 9, 2011 Share Posted December 9, 2011 This will surprise you http://forum.mtimag....php?p=7965#7965 Link to post Share on other sites More sharing options...
Prof Klyzlr Posted December 9, 2011 Share Posted December 9, 2011 This will surprise you http://forum.mtimag....php?p=7965#7965 Dear Jack, No surprise at all. handing the throttle to a set of "random modellers" resulted in ChicagHO Fork" turning out a full 3:2:2 - 4-car "nook" session approx every 20 minutes. This was largely comprised of "thinking and driving" time, When we injected a bit of "...hold on a mo, you need to pump up the brakes... now let the brakeman walk to the turnout to throw it... now you can move..." style proto-ops actions, and the time to switch the same consist at approx 10smph blew out to 35 minutes. As discussed on the latest ModelRailRadio podcast, use of walkie-talkie radios in proto ops actually _adds_ significant time to a proto train-crews switching moves, independently of how long it takes to actually run the train and get the switching done... Happy Modelling, Aim to Improve, Prof Klyzlr Link to post Share on other sites More sharing options...
Jon Gwinnett Posted December 10, 2011 Share Posted December 10, 2011 That's certainly the ambiance i have tried to replicate. Some good learning points too. Also, as they stretch the couplers and sort knuckles out, there's quite a lot of similarity to the "Kadee shuffle" I thought? Maybe my next plank (sorry Prof, small layout!) should be a NJ glassmaker! Link to post Share on other sites More sharing options...
298 Posted December 10, 2011 Share Posted December 10, 2011 That's certainly the ambiance i have tried to replicate. Some good learning points too. Also, as they stretch the couplers and sort knuckles out, there's quite a lot of similarity to the "Kadee shuffle" I thought? As long as you give enough time for the crew to walk to the cars and pull the cut bars, undo the air hoses, set the brakes, etc.... Link to post Share on other sites More sharing options...
Supaned Posted December 10, 2011 Share Posted December 10, 2011 Andy , I'm not sure they'd split the air hoses. As I understand it, the hoses will automatically part when they are pulled taut (the ones here have the same design) , and I've seen clips where they just pull the coupler lever and draw away , leaving the uncoupled car in place. Link to post Share on other sites More sharing options...
signalmaintainer Posted December 11, 2011 Share Posted December 11, 2011 . . . undo the air hoses. . . Naw, they just pull apart when the cut is made. Much safer and less pounding on the eardrums when there's 90 psi of air in the brake line. I find that switching on a model railroad, when done at realistic speeds and with regard given to crew movements, flagging, realistic coupling, etc., can almost take as long as on the prototype. (As an aside, it seems the OP on the other forum has his panties in a bunch for some reason about this topic.) Link to post Share on other sites More sharing options...
CraigZ Posted December 11, 2011 Share Posted December 11, 2011 Naw, they just pull apart when the cut is made. Much safer and less pounding on the eardrums when there's 90 psi of air in the brake line. I find that switching on a model railroad, when done at realistic speeds and with regard given to crew movements, flagging, realistic coupling, etc., can almost take as long as on the prototype. (As an aside, it seems the OP on the other forum has his panties in a bunch for some reason about this topic.) I've been an operator on a 850 sq ft layout here for 20 years (now THAT'S terrifying but I digress). We run a fast clock for the timetable but one thing can't really be run to the fast clock and that's shunting/switching. The time consumed there, if done prototypically, is darn near what it takes the prototype to do it... Link to post Share on other sites More sharing options...
F-UnitMad Posted December 12, 2011 Share Posted December 12, 2011 Andy , I'm not sure they'd split the air hoses. As I understand it, the hoses will automatically part when they are pulled taut ... The same thing happens when Helper engines uncouple from the rear of a train... On the other hand, air lines do have to be connected by the switchman when cars are being coupled up, so a bit of time should be allowed for that... Link to post Share on other sites More sharing options...
298 Posted December 12, 2011 Share Posted December 12, 2011 So I have to split the train and press f-whatever for air release when the couplers have parted. But what about closing the valves...? Link to post Share on other sites More sharing options...
Jon Gwinnett Posted December 12, 2011 Share Posted December 12, 2011 The same thing happens when Helper engines uncouple from the rear of a train... On the other hand, air lines do have to be connected by the switchman when cars are being coupled up, so a bit of time should be allowed for that... Do they always connect the air hoses when switching? Or can they haul a car with the air drained, isolated or whatever, if they are going to be making several moves. Not sure I've explained quite what i meant, but I'm thinking of what happened in the UK, where in the old days of vacuum braked stock, if wagons were being shunted they "pulled the string" and destroyed the vacuum so that wagons could be moved around without having to stop and couple vacuum hoses. Link to post Share on other sites More sharing options...
RMweb Gold Ramblin Rich Posted December 12, 2011 RMweb Gold Share Posted December 12, 2011 I feel that this is a situation where DCC sound might help with creating a more correct timing sequence - even if there is no movement, if people hear things happenning, they may be more likely to accept that the operation is realistic? Link to post Share on other sites More sharing options...
RMweb Gold Oldddudders Posted December 12, 2011 RMweb Gold Share Posted December 12, 2011 I think you must be able to isolate the brakes, otherwise during hump and fly shunting, the moment the brake hoses part, the car would come to a stand, which is not what you want at all.That's also why, when the train has been made up, and the road engine is attached, it takes 3 fortnights for the whole consist to pump up, surely? [Loved signalmaintainer's expression "has his panties in a bunch". We tend to say "has his knickers in a twist"!] Link to post Share on other sites More sharing options...
298 Posted December 12, 2011 Share Posted December 12, 2011 I feel that this is a situation where DCC sound might help with creating a more correct timing sequence - even if there is no movement, if people hear things happenning, they may be more likely to accept that the operation is realistic? As long as that can include a loco sat with it's orange rotating beacon on and a cab door open whilst the crew have lunch or wait for a car to be loaded... Link to post Share on other sites More sharing options...
Supaned Posted December 12, 2011 Share Posted December 12, 2011 Even a "quiet" motor like YVT 298 must have a compressor that kicks in now and again , which would provide a bit of noise. Link to post Share on other sites More sharing options...
298 Posted December 14, 2011 Share Posted December 14, 2011 Even a "quiet" motor like YVT 298 must have a compressor that kicks in now and again , which would provide a bit of noise. It has and I've got an audio of it when idling for a custon sound chip. It is on the "to do" list, but the thing that has always put me off sound is you can get ones for specific diesel models with umpteen choices of horn but the traction one is generic. Trains also make a distinctly different noise when running on the street and there's no easy answer to that. Link to post Share on other sites More sharing options...
CraigZ Posted December 16, 2011 Share Posted December 16, 2011 I think you must be able to isolate the brakes, otherwise during hump and fly shunting, the moment the brake hoses part, the car would come to a stand, which is not what you want at all.That's also why, when the train has been made up, and the road engine is attached, it takes 3 fortnights for the whole consist to pump up, surely? [Loved signalmaintainer's expression "has his panties in a bunch". We tend to say "has his knickers in a twist"!] Isolating cars - there's isolation valves on each end of the car. Turn the hands on both ends of a car or cut of cars and it's called "bottling the air", at least around here anyway. That allows the cars to roll freely as the air is 'bottled up' between the isolation valves and keeps the brakes released. Of course when the cars are reassembled in a train somebody has to walk the train and reopen those valves - if one gets missed it will show up in the brake test run before the train departs the yard. And here in the south, it's 'has his panties in a wad'....and losing one's temper is 'losing your religion'.... Link to post Share on other sites More sharing options...
dave1905 Posted December 17, 2011 Share Posted December 17, 2011 Isolating cars - there's isolation valves on each end of the car. Turn the hands on both ends of a car or cut of cars and it's called "bottling the air", at least around here anyway. That allows the cars to roll freely as the air is 'bottled up' between the isolation valves and keeps the brakes released. Of course when the cars are reassembled in a train somebody has to walk the train and reopen those valves - if one gets missed it will show up in the brake test run before the train departs the yard. There is a train line valve on each end, commonly called the angle cock. Under most US rule books, "bottling the air" is against the rules because its dangerous and not particularly effective. The rules require the angle cock to be left open on the detached portion of the cars. Whether or not you switch with air depends on what the crew is doing and which crew is doing it. If Its a local crew setting out a car they will set it out with air. If its crews classifying cars in a yard, they will switch without air. if its a train handling a cut of 100 cars they will handle it with air. On each car, opposite the brake valve is a "bleed rod" a rod that runs crosswise on the car and ends in a loop on either side of the car, just below the side sill. When it is pushed or pulled, it bleeds the air out of the brake system on the car allowing it to roll free. When a cut of cars is to be classified the switch crew or the carmen walk the train and bleed off the air. If a car has been detached from an engine for more than 4 hours chances are the brake system has bled off regardless of how the angle cocks are set. Some cars require less than a minute for the brake system to bleed off after the engines are disconnected from the cars. Link to post Share on other sites More sharing options...
M Graff Posted December 17, 2011 Share Posted December 17, 2011 The general misconception as I understand it, is how the airbrakes actually works. What is usually said is that you need air pressure to get the brakes free in a train, but that is only half of the truth.... The Wabco system works on equilibrium of air pressure, and applies the brakes when the train line pressure is reduced. But if there is no pressure in the train line, then there is no force acting on the brake cylinder, and hence no brakes! The pressurisation of a long train can take considerable time; 5-10 minutes. That is something rarely done on a model railroad...... Link to post Share on other sites More sharing options...
Supaned Posted December 17, 2011 Share Posted December 17, 2011 I get it now. The escaping air is the from the brake pipe on the cut of cars (or individual car) being spotted. Venting the train brake pipe will apply the brakes , while there is air in the system , but as has been stated , after a few hours this will leak away and the car could roll away unless secured by a handbrake or scotch. The angle cock on the brake pipe of the car or locomotive being moved away must be closed or the brakes would apply as soon as the air pipes part. So as well as pulling the cut lever , time should be allowed for the brakeman to close the angle cock on the portion of the train that will move away from the spotted car or cars. Link to post Share on other sites More sharing options...
dave1905 Posted December 17, 2011 Share Posted December 17, 2011 The general misconception as I understand it, is how the airbrakes actually works. What is usually said is that you need air pressure to get the brakes free in a train, but that is only half of the truth.... The Wabco system works on equilibrium of air pressure, and applies the brakes when the train line pressure is reduced. But if there is no pressure in the train line, then there is no force acting on the brake cylinder, and hence no brakes! The pressurisation of a long train can take considerable time; 5-10 minutes. That is something rarely done on a model railroad...... The Westinghouse air brake uses the train line as both a communication method and a supply line. There are several components, an air pump to supply ppressurized air, a control valvle used by the engineer to apply an release the brakes, the train line that connects each car, the brake valve on the car, the air reservoir on the car and the brake cylinder. When everything is hooked up and the control valve is released, the control valve sends air into the train line and since the train line pressure is higher than the pressure in the reservoir, the brake valve routes air to the air reservoir. At some point the reservour fully charges and the reservoir and train line have the same pressure. When the engineer applies the brakes with the control vlave, he lowers the pressure in the train line, The brake valve on the car senses the lower pressure and the a valve on the car moves to vent pressure from the reservoir to the brake cylinder, causing the brakes to apply. When the pressure in the reservoir matches the pressure in the train line, the brake valve equalizes, maintaining the pressure in the brake cylinder. If the engineer applies the brakes again, the pressure drops in the train line, the brake valve moves to vent more pressure from the reservoir to the brake cylinder and the brake cylinder applies more braking force. If the pressure differential between the train line and the reservoir drops by a large amount all at one time, I can't recall the exact amount, but its is about 20 psi or so, the brake valve moves to vent the entire emergency reservoir into the brake cylinder, applying the most braking forse possible. When the engineer moves the control valve to release, the air pressure builds in the train line. The brake valve senses the change in the pressure and routes air to the reservoirs and vents the pressure from the brake cylinder to the atmosphere, releasing the brakes. When the pressure in the train line equalizes with the pressure in the reservoirs, the brake valve centers and stops charging. So the pressure in the train line is not directly connected to the brake cylinders at all. The car brake valve is between the trainline and the rest of the equipment. The trainline charges the reservoirs and communicates the instructins through differences in pressure. The brake valve on the the car applies the brakes using the air from the reservoirs. Link to post Share on other sites More sharing options...
dave1905 Posted December 17, 2011 Share Posted December 17, 2011 So as well as pulling the cut lever , time should be allowed for the brakeman to close the angle cock on the portion of the train that will move away from the spotted car or cars. Yes, the angle cock on the portion attached to the engine should be closed prior to uncoupling, IF they are switching with air. A 10-20 second chore. Setting the handbrake is the most time consuming part. The hard part is coupling cars up and cutting in the air when making a joint between a cut with air and without air. If the angle cock is opened too quickly it will cause too rapid a drop in pressure on the portion with air and put it in emergency. Link to post Share on other sites More sharing options...
RMweb Premium BR60103 Posted December 18, 2011 RMweb Premium Share Posted December 18, 2011 Someone once observed that in the US Couplings join automatically but the air hoses must be done manually. Couplings are uncouple manually but the airhoses are automatic. Link to post Share on other sites More sharing options...
dave1905 Posted December 19, 2011 Share Posted December 19, 2011 I've been an operator on a 850 sq ft layout here for 20 years (now THAT'S terrifying but I digress). We run a fast clock for the timetable but one thing can't really be run to the fast clock and that's shunting/switching. The time consumed there, if done prototypically, is darn near what it takes the prototype to do it... One must take into consideration the era of the layout also. The video referenced was a modern operation where there was a two man crew (engineer-foreman/conductor), and the trainmen weren't allowed to get on or off moving equipment. If you go back 20 years or so the crew size would be a 3 man crew, engineer-foreman/conductor-switchman/brakeman and if you go back 30 years there is at least one more brakeman and possibly a fireman. Plus in earlier eras, the crew members would be able to get on and off moving equipment. All of that would cut the switching time by a third to a half. Link to post Share on other sites More sharing options...
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