|
|
|
|
|
Welcome Visitor. First time here? Like what you see? Bookmark us for when you are bored, and check out 'top shots' and 'fantastic (editors choice)' in the menu above, you won't be dissapointed. Join our community! click here to sign up for an account today. Sick of this message? Get rid of it by logging-in here.
These little engines, although working road service, were still switchers at heart (loaded T.E. quickly). If the GP9 was leading, the switchers will be shoving against the slower to load road unit (with a possible result of a jack knife). Best keep the little guys in the lead pulling.
I should have included RS18 when I mentioned GP9 in my comment above.
Larry thats not quite true. That would apply with newer power like if it was a GP40-2 compared with a GP9 as they load at different amps. These units all load at basically the same rate and the HP are very similar. You will see many picture of mixed power on trains. Jack knifing does not happen because of a higher hp power leading.
That’ll learn me for quoting off the top of my head, rather than taking the time to find my CN 697 (5-77) booklet. You’re correct ngin, they can be in any combination when pulling. But if you’re going to be shoving with pure strings or any combination of GP9, GMD-1 or SW1200rs, great care must be taken with these units as they develop high T.E. And can turn rail or jackknife when shoving a long string if proper care is not taken.
Actually Larry, that only applies with locomotives with non-aligned couplers. In the good old days the couplers were non-aligned, which basically meant that the coupler could move side to side allowing the couplers and draft gear to slide to one side which can cause it to jack knife. On CN almost all locomotives are equipped with aligned couplers. The hand full that do not are listed in the enginemans operating instructions. Not so fun fact. The derailment that happened years ago out near Liverpool where the York and Kingston Subs meet was caused because the train had 3 GO F59PH’s behind the CN consist. The GO units had non-aligned couplers and the weight of the train coming downhill in dynamic braking caused the units to jack knife. Since then, only one non aligned locomotive is allowed to be moved on each train.
you cant fool Captain Hall !
The photo is from 1968, my booklet is from 5-77, just past the date of the photograph. Seemed like a date applicable source to quote considering the photo date. But if you want to quote current circumstances, then i guess I stand corrected. Again.
LOL@snake.. you can, but ya gotta get up early
.
@Larry. You may indeed be correct. I have my old manuals from 81 until they combined everything. I am not here to prove you wrong my friend. I am just saying there could be many reasons the consist is this way.
Draft gears don’t slide sideways, they are fixed in the draft pocket. The yoke surrounds the draft gear and connects to the coupler with a pin, allow the coupler shank/head to pivot sideways. Same with most passenger cars, easy to see on the tail end of a VIA train with LRC cars. Most freight cars use a crosskey instead of a vertical pin.
@5248. When i say draft gear i am talking about the entire assembly not specifically the housing. Auto racks and parts cars couplers can slide quite a distance and this sometimes causes crossed couplers. Some older power have non aligned couplers and that is why they have certain restrictions.
I think the reason may have been that some early smaller EMD units like these SW’s didn’t have automatic backwards transition – they had manual backwards transition.
When one of those was trailing in a consist with a leader with fully automatic transition, the engineer needed to do something like briefly returning the throttle to idle to trip the backwards transition for any manual transition units trailing (or else you’d overload the main generator). Perhaps making those units lead helped avoid that situation.
@MrDan..not sure about the SW1200RS’s as all the ones i drove tended to make transition together and they did have a switch that you could move between road and yard.
Zing.
From what I’ve seen on CN’s own locomotive datasheets, the SW1200RS units (and GMD1′s) are listed as having automatic forward transition but manual backwards transition. All the standard road stuff like GP9′s and RS18′s had fully automatic transition. Rebuilts like the 7300′s also got fully automatic transition.
Running SW1200RS units together or leading wouldn’t be a problem, from what I’ve read it’s if one was trailing a unit like a GP9 with fully automatic transition. The trailing SW1200RS wouldn’t make the manual backwards transition without briefly reducing the lead unit’s throttle to idle. If the SW1200RS was leading, it would be run as a unit with backwards-transition and operate fine, and the trailing GP9 would make transition automatically as it normally would. This was an issue with some earlier CP units as well, notably the E8A’s when they were used as trailing units on the Atlantic Ltd (a crew out west was running a freshly overhauled one in a freight consist once and fried a brand new MG because they didn’t know about the manual backwards transition).
That selector would be the “Road Service Switch”, allowing faster loading depending on what use it was working in.
Boy, I’m glad I found this photo when I did, or the Comments would be into a 2nd edition by now.
This is the Niagara Falls turn, exToronto as 461 and back home as 462. The date is Dec 23/67 and the trailing 2 roadswitchers are IDLING !
(likely if for no other reason than not required).
Plus, all 4 of these GR-12′s were assigned to Montreal Yard at this date, so they are captured out of their usual territory. ( I had just recorded 1293 freshly repainted at CN Walkley Yard 2 weeks prior).
LOL@mercer. Thanks for the post. Conversation is a good thing.
At one time, we had a rule on CP that an SW1200RS must not be placed behind 6 axle power. It was supposed to be cut in the middle of the consist. That meant for example, if we lifted one of the “pups” enroute, the big power had to be split to place the small unit in the middle. I believe this was due to lack of coupler alignment feature. This rule was sometimes not known or ignored, & in later years the units may have been modified. I’ll bet there are photos on here or out there, that depict both examples of placement.
Also, with regard to shoving with power consists, CP has (had?) a rule that limited powered axles when shoving. If it was necessary under that rule to cut out some units, those closet to the cars being shoved were to be powered, and the rest cut out, excepting the leader, account need to watch loadmeter. required that units in the rear of the consist
ignore last 9 words above, I meant to delete them in composing the message. Senior moment perhaps?