Taking this topic off the oil-train thread: There would only be three displays in the cab. Normally all FREDs give the same message, so one display would be sufficient. If controls for mid-train power are flexible so that when a train is cresting a summit, the part going downhill can be in brake mode while power still is applied to the rear half (as an example) then two displays would obviously be required. A third display only lights up when there is an errant FRED that is not presenting data like the rest of its group, and the display tells which FRED it is.
Power for the FREDS might be charging batteries with small wind turbines that use the air draft under cars driving small alternators and rectifiers.
Again each FRED would connect to two air hoses as well as joining them mechanicaly. Each would hang off of a grab iron on the end of either car and would both transmit data and respond to brake commands of the engineer.
EOTDs are mainly air-powered anymore. So that’s already done.
Have to change the federal rules before you hang them off grab irons. FRA is pretty picky about that - safety device and all. (not a huge deal, but one more small issue to resolve).
Locomotive head end boxes are going to have to be redesigned to accept multiple EOT IDs. Then will each one have to be in working order? If one craps out and gives a front-to-rear no comm message, are you now restricted in your operations? All kinds of rules about EOTD failure currently on the books. And then would each EOTD have to be tested to make sure it can dump the air from the head end? That’s required now.
Again, not insurmountable objects, but objects none the less. And EOTDs aren’t cheap, so by the time you do this - it may be cheaper just to install ECP brakes.
Redesigning the head end boxes is a very easy fix. You wouldneed to change the software to accept multiple EOT information and keep track of what is going on. No big deal for a good programmer…
I agree with all the comments. This would not preclude having new cars built with all the stuff built-in and still compatible with the portable stuff. Regarding the logistics, the first application would be for unit oil trains where the consist stays together and the FREDs would be removed only for the required inspection and testing cycle, which would probably affect the tankcars themselves. The last application of this equipment would be when most of the total freightcar fleet has electronic control braking, many years from now, and this portable equipment will be used to make older cars usable with newer cars.
You can’t mount the MTD’s (mid train devices) on the side of the car, that would provide clearance problems to structures and adjacent tracks.
You would have to have some way of connecting it to the air lines without the hose dragging on the track, but adjust to mulitple variations of mounting arrangements and still have flex to adjust to different draft gear arrangements.
How do you make a set out with this arrangement? The set out has an MTD in it, if you turn the angle cock at the joint and come off with the head end, the EOT and rear MTD’s going in emergency will put the head end in emergency.
At least the railroads will have a choice, take the newest and otherwise compliant cars out of service and equip them or add the EOTD-modifieds to existing consists, even while they are loading or unloading.
You really don’t need any special way to mount an eotd in the middle of a train. They latch on to the side of the coupler, so they can be hung even if the cars are coupled.
I fail to see the purpose or even why you would want two EOT’s. To the best of my knowledge, DPU’s can be operated as separate sets. How often that this is done, I don’t know. Back when I operated trains with Radio Units, the mid-train power was set up to mirror the head end power. (And if I remember correctly, even they could be set up as separate sets.) There was no problem with running them the same and no need for a second EOT.
Wabtec has a chart that gives the emergency application stopping distance of several test trains, including one with ECP brakes. They identify those test trains by the following designations:
ABDX
ABDW
ABD
ABDX+1 EOT-ES
ABDW+1 EOT-ES
ABD+1 EOT-ES
DIST. POWER +1 REMOTE
ABDX+2 EOT-ES
ABDW+2 EOT-ES
And we can’t forget that while the sole purpose of the brake line under ECP becomes keeping the reserviors charged, there is still a finite amount of air that can be supplied, so it is still possible to “p!ss away” one’s air… Might have to work harder at it, but it’s still possible.
The devices Mr. Klepper is describing aren’t EOTDs (except insofar as parts of existing EOTD systems could be used OTS or with minor and cost-effective modification to produce them). They represent only a limited part of the EOTD functionality, the ability to provide an air-brake control valve at some point in the trainline. In the simplest version of the system, all these valves would be slaved to the brake valve in the cab, giving the advantage of ‘lightspeed’ actuation at distributed points in the train. The abbreviation MTD is a good one.
I think Mr. Klepper is planning to have these valves be individually addressable and to have the capability of at least a limited amount of differing modulation (I have to be careful not to say ‘differential’ as that has a different technical sense in the present discussion!) There are a number of ways that multiple MTDs could be ‘connected’, and how the system could determine the relative number and position of devices in a consist. The head-end device (as reprogrammed cf. Caldreamer) would then be able to address each of the devices appropriately, for example to modulate the rate or amount of application at each point, or to close one or more valves while permitting further exhaust by others.
Note that even a slow and ‘quantized’ version of graduated release would be difficult to implement on this kind of system – unless I’m nisunderstanding how the valves work. So it’s strictly applicable to the scenario of better-controlled rapid or emergency braking down to a full stop. The thing I have to wonder is this: that scenario is almost 100% of what the Feds are calling for from a ‘safer’ HHFT brake system. (We all know graduated release, differential braking, etc. can improve train handling in some respects, but we’ve also begun to disa
Excerpt from Train Accident Reconstruction and FELA and Railroad Litigation (2005)
Control valves are central to automatic air brake operation and performance. In 1933, AB control valve equipment was introduced on freight cars. This equipment featured the AB valve and a two-compartment auxiiary and emergency air reservoir to allow for both service and emergency braking of freight trains. The AB valve equipment had faster transmission, release, and charging times than previous equipment, and also controlled brake cylinder pressure buildup times. AB control valves developed brake cylinder pressure in three stages:
1st stage, 15 psig brake cylinder pressure in one second.
2nd stage, 15 psig brake cylinder pressure in seven seconds.
3rd stage, 47 to 60 psig brake cylinder pressure in two seconds.
In 1963, the ABD control valve was introduced and used until 1976, when the ABDW control valve was adopted by the Association of American Railroads (AAR) as the new standard for freight train brakes. The ABD and ABDW control valves were more reliable, had quicker release times, and were more sensitive to pressure differentials than the AB valve. The ABD and ABDW control valves develop brake cylinder pressure in two stages
But the full service application distance is only marginally more than the emergency stop distance with ECP, from slide 7. Surely stopping in a significantly shorter distance in normal service is at least as important as the performance in the less likely emergency situation.
The stopping distance for a full service application with ECP is effectively half that of a train with ABD valves and no EOT valves, and better than any of the non ECP options.
ECP works, it is proven in applications identical to normal USA operation and it is made by local USA suppliers. It was invented here (if here is the USA).
It is not an untried system being forced on the railroads. It is a proven system that works well, particularly with unit trains (like oil trains).
ECP has been TESTED in controlled enviornments - as such it it wholely untested in the real world of loose car railroading - every car, even those in dedicated unit train service get incorporated into the loose car world from time to time and end up away from their dedicated service center. To date, my understanding is, there are competing forms of ECP that are not compatible with each other.
The braking that is being taught to Engineers at present is Dyn