In January’s issue of Trains in an article called A day on the road, Douglas Fear talks about GE AC4400CW’s having an automatic distant measuring device. What is this and how does it work? When would an engineer use it?
Thanks for the info.
a trip odometer that counts backwards from a preset number.
You dial in the train length and then hit the start button and it will count down the feet to zero.
a trip odometer that counts backwards from a preset number.
You dial in the train length and then hit the start button and it will count down the feet to zero.
You use to know when the rear end of the train has passed the point where you pushed the button. For example, when entering a siding and wanting to know when the train is clear of the switch.
Works great until the wheel diameter changes or slips[:D]
it can be either preset to the train length that is shown on your train documentation…or it can count up or down from 0… it is used to let engineers know when thier train is clear of a siding or main track… a slow order… a slower speed zone… or when the rear end has cleared a road crossing should the train have to to stop for some reason and dosnt want to block the crossing…just to name a few off the top of my head…
to use it…its just a matter of pushing a few buttons on the computer screens …or on older locomotives…a button where the HTD box is on the controll stand…
and mudchickin…that is true to a point… thats why we have messered mile posts here and there… not only do we check the speed recorder at the messered mile post…but we are also to test the distance counter to see if it is calibrated …
situations where the distance counter isnt working right and i dont have a messered mile post to check it with… alot of times if we are passing a stoped train…i would ask the crew to let me know when my last car was going by their engin …i would start the counter as soon as my engin reached thiers…and stop it when they said the last car was going by to get an accorat reading of my trains length…
csx engineer
On the new es ac&dc’s they can count both up and down, when going through a measured mile I have it counting up from zero, when going in sideing, crossing over or a slow order I have it counting down from my train length it beeps at me to let me know when I am in the sideing, crossed over or through the slow order. The reason I go up from zero in a measuerd mile is to check the accurcy of the counter. They are almost the same as the dash-9’s
Rodney
Very interesting.
The distance counter is tied into the speedometer. If the speedometer is fast the distance will measure more, if the speedometer is slow the distance will measure less. If you are good at math and you know how much your speed is off, you can calculate how long your train should be and vice versa.
one good thing about the -9s is the computer speed check… we can check the speed between a messered mile post without haveing to have a watch with a second hand or a stop watch… its all done with a few pushes of the button…hit start and then stop and the computer will tell you your average speed between the mile posts… the trick to making sure the speed recorder is reading right is to maintain a set speed and try not to speed up or slow down durning that mile so it dont screw up the speed check reading…becouse the computer will just take the average speed should you start slower into the speed check…and come out faster at the onther end of the mile… on a long train…its not so much an issue…but on a short or a light one where you can get speed fast… it will screw with your test results…
csx engineer
Amen to that CSX when I go through a measured mile I keep my speed as close to constant as I can to check the speedometer and the counter.
Rodney
there is also a speed check program that I have on my palm pilot that does a good speed check as long as you keep your speed consistent and you have a test mile to reference, as csxengr said.
csxenginner98,
So based on your comparisons, how accurate are these distance devices?
Thanks,
Michael
As Big Jim said above, they’re as accurate as the speedometer, although I’ve had a couple that I can’t explain, they would measure a good test mile but the speedometer would be off, or vice-versa. As I said, makes no sense but that was my results. Had one just a little while ago that measured about 15,500 feet to a mile, but the speedometer wasn’t especially far off.
overall they are accurate enought to get the job done…but once in a while…you will get one that is realy realy realy off…like it it was calibrated to count in kilometers insted of feet or something…
csx engineer
Another nice thing about the GE distance counters on the “Dash 9” is that you can keep up with the length of your train when setting off and picking up.
UNFORTUNATELY!!!
The clowns at GE decided we had it too good and designed the retrograde EVO units and screwed up even more by changing the distance counter to one that is only good for counting up or counting down and can’t keep up with itself. Where GE finds the people that think they are doing us a favor is beyond me!
at least its better then the EMD counters on the sd70 and 80macs…1 counter and 2 stations to use it at… the engineers side and at the conductors desk and they both where tied into the same counter… i would be counting down a length for what ever reason…and the conductor …being board…desides to play with the counter… like seeing how close he can get to 1000 feet without going over or something like that… so my messerment i was needing is now history…
now that is some real good design on EMDs part…
csx engineer
Since this topic was about GE distance counters, I decided not to comment on how stupid the EMD counters are[:0]
lol…i brought it up for you…lol post topics hold no bounds for me and my willingness to talk about things that suck
csx engineer
The new gevo’s that we have on BNSF has 2 counters there has been times where I have had both of the going.
Rodney
Why don’t the RRs put a GPS into every FRED? That way you’d know exactly the length of your train (locos GPS coordinates - FRED’s coordinates) and could figure indirectly that you are past the switch. Alternatively, the coordinates of the switch are known. That would tell you directly whether the end of train is past the switch.