tree68I've also heard that HP=speed. This is where the HP/ton factor comes into play. If you want to get the load over the road quickly, pile on the HP. If you just want to get the load over the road, put on just enough power to do so.
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monon99 With the train stretched on a grade it can be tough to restart a train. Sometimes sand, a little independent brake to keep the wheels from hopping, will get the job done. If your power just doesn’t have the grunt(let’s say an emd), you can set a little air, shove back gently to bunch the train, set full service when the eot beeps and says movement. Now take a deep breath, let everything settle down. Go to suppresion on the air brake, wait for that to settle, no hissing. You will get a “slow release” like from a minimum set. Brakes will now release one car at a time from the head end to the back(assuming no dp). Now you can throttle out and start moving a few cars at a time. You better have a good feel of your train. Gradually you can move the whole thing. I’ve used this a lot on the hilly Monon subdivision, thankfully the skilled hoggers who worked that line taught me well.
With the train stretched on a grade it can be tough to restart a train. Sometimes sand, a little independent brake to keep the wheels from hopping, will get the job done.
If your power just doesn’t have the grunt(let’s say an emd), you can set a little air, shove back gently to bunch the train, set full service when the eot beeps and says movement.
Now take a deep breath, let everything settle down. Go to suppresion on the air brake, wait for that to settle, no hissing. You will get a “slow release” like from a minimum set. Brakes will now release one car at a time from the head end to the back(assuming no dp). Now you can throttle out and start moving a few cars at a time. You better have a good feel of your train. Gradually you can move the whole thing.
I’ve used this a lot on the hilly Monon subdivision, thankfully the skilled hoggers who worked that line taught me well.
Thanks. I was wondering if that sort of thing was ever done.
SD70Dude, right about the SD40-2. A yard that I watched for a long time had a SD40-2 switcher, then changed to an SD60, now have to ease starts to move the same amount of cars.
What is the HP rating of a typical car-moving winch?
Greetings from Alberta
-an Articulate Malcontent
No need for 5 horsepower -- a 0.1-horsepower person can move a train if his winch rope runs around a sufficient number of pulleys.
Power is force times speed -- in other words, force is power divided by speed. If you can accept the necessary low speed, you can produce any needed force from any power source. As long as power remains constant, you can double the force by halving the speed, and you can keep doing that forever.
tree68I've heard that a 5 HP Briggs and Stratton could move a sizeable train (on flat ground) given the traction and suitable gearing. Not fast, but it could move it. I've also heard that HP=speed. This is where the HP/ton factor comes into play. If you want to get the load over the road quickly, pile on the HP. If you just want to get the load over the road, put on just enough power to do so.
I've also heard that HP=speed. This is where the HP/ton factor comes into play. If you want to get the load over the road quickly, pile on the HP. If you just want to get the load over the road, put on just enough power to do so.
Watched a B&O SW-1 with all of 600 HP and 30 years service move 8700 tons of cement out of Clark Ave. Yard in Cleveland to Brooklyn - of course it took 3 hours to go that 5.7 miles.
Never too old to have a happy childhood!
I've heard that a 5 HP Briggs and Stratton could move a sizeable train (on flat ground) given the traction and suitable gearing. Not fast, but it could move it.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
i agree
my point is that the drawbar force is not proportional to horsepower. it's inversely proportional to speed.
so maximum force is at the lowest speed and of course limited by max tractive effort (i.e. weight on drivers)
greg - Philadelphia & Reading / Reading
No diesel locomotive can generate full horsepower at its wheelrims at 1 mph. At 30 mph today's 4400 hp locomotives can produce maybe 3800 hp at the wheelrims; at 1 mph, 3800 hp would be 1,400,000 pounds of TE.
gregcmy understanding is that max horsepower in a diesel locomotive is available at any speed. Horsepower is work / time. work is force multipled by distance
Maximum 'horsepower' in a diesel locomotive is imposed by the characteristics of the prime mover. But the curve close to zero road speed is nowhere near as extreme as often drawn (especially in early EMD 'propaganda') as the effective instantaneous 'tractive force' (which is the only thing that matters when calculating resultant with train resistance) is both adhesion- and traction-motor limited.
Even with AC drives there are some limitations on the practical near-locked-rotor torque that can be produced from "maximum horsepower for traction" at the motors (e.g. from the combustion engine through the generator, inverter system, and cabling losses). If you look at how AC motors generate torque off synchronous speed you will understand the electrical 'slip' involved; modern synthesis drives can maximize the effective torque at a given speed.
Of course, you're familiar with DC motor limitations, which are far more severe, and dramatically limit both applicable torque and effective duty cycle below about 11-12mph road speed.
There are ways to overcome much of the low-speed disadvantage of the reciprocating steam locomotive -- some of which are nominally wasteful of steam mass flow and 'associated considerations' but which can be made efficient with the correct forms of traction control and valve gear.
Lithonia OperatorNow the train is stopped on the ruling grade, with no slack. Can the engineer get the train going?
my understanding is that max horsepower in a diesel locomotive is available at any speed. Horsepower is work / time. work is force multipled by distance
at least on level grade, the force applied needs to overcome the friction of the bearings which is dependent on speed. But consider, for a moment that the friction, hence force is constant at any speed. Then the horsepower required depends on the work being done and is proportioinal to the distance the force is applied over
this means half the horsepower it required at half the speed, or that twice the force is available at half the speed.
when going up a grade, when force must also overcome a percentage of the weight of the train, the available horsepower will limit the distance the train can move at the higher force.
so when facing a steep grade, the distance traveled per unit time may be small, but not zero.
of course this is not true for a steam locomotive where horsepower is not constant and depends on speed.
GARY WHITTTree, I was just browsing around. I am from Milford MI. also.
MHS Redskins, Class of '68.
I used to live on the south side, at the top of the hill.
A discussion that probably belongs in the Classic forum, however, it speaks to some timeless issues, no matter the motive power being used.
https://www.youtube.com/watch?v=AkBX5JTS60A&feature=youtu.be&fbclid=IwAR3LQKl28EhsFdIAcXzy0hWHfNz_TwoCLyncAppK5AGw1GZD7qXiBPjMmys
Lithonia Operator Let's take your average freight train, in this case one that has enough locomotive power to deal with the ruling grade on the line (according to guidelines), but not much more. 1) Let's say that on level ground, the engineer rolls forward slowly, taking up slack. Then, once all slack is stretched out, he stops without letting any slack occur. The train is fully stretched out. (This is hypothetical.) Could he now start the train moving, all at once? If the answer to the above is Yes, let's say this train proceeds until it is on the ruling grade and suddenly the engineer needs to bighole it. (Let's say he sees people on the track, but stops before hitting them, then the people leave.) Now the train is stopped on the ruling grade, with no slack. Can the engineer get the train going? Or will they have to double the hill?
Let's take your average freight train, in this case one that has enough locomotive power to deal with the ruling grade on the line (according to guidelines), but not much more.
1) Let's say that on level ground, the engineer rolls forward slowly, taking up slack. Then, once all slack is stretched out, he stops without letting any slack occur. The train is fully stretched out. (This is hypothetical.) Could he now start the train moving, all at once?
If the answer to the above is Yes, let's say this train proceeds until it is on the ruling grade and suddenly the engineer needs to bighole it. (Let's say he sees people on the track, but stops before hitting them, then the people leave.) Now the train is stopped on the ruling grade, with no slack. Can the engineer get the train going? Or will they have to double the hill?
Another thing to remember about slack... There is free slack which is the just the small bit of space between the parts in the coupler and draft gear. That actually doesn't add up to all that much in the train.
Most of the slack is from the draft gear. In the old days, it was a spring. Now, it is rubber pads. It's main job is to protect the freight car from damage when coupling. It cushions the blow so you can couple up at a few mph and not destroy anything. So, when you take slack, you are compressing all the draft gear (actually shearing rubber pads in one direction). When you have the train stretched, you have the draft gear extended some. When you start to pull, you are actually extending the draft gear some more - so you never really have a "solid" train, it's always a bit of a slinky.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
zugmann BigJim Why not? Ours were. But they were for when the locomotive was fresh out of the factory floor. Oh yeah, those 2 beater C40-8Ws are good for that train! (maybe 20 years ago, and with sand, and with a hill that isn't covered in wet leaves). Some of those engines were so ragged they could barely pull themselves.
BigJim
But they were for when the locomotive was fresh out of the factory floor. Oh yeah, those 2 beater C40-8Ws are good for that train! (maybe 20 years ago, and with sand, and with a hill that isn't covered in wet leaves). Some of those engines were so ragged they could barely pull themselves.
Not around here. If the units weren't having some electrical or mechanical problem, they would pull what they were rated. The only problems I ever remember having trouble with were a couple of foreign units from out west that wouldn't pull a greasy string out of a cat's petoot!
timzThe 1987 CSX empl TTs did show ratings. As I recall an SD50 was rated 18000 tons eastward over the Magnolia Cutoff, where the eastward climb is about 0.1% compensated.
Magnolia Cutoff -
MILLR4 CUMBO4 BAQ 0 BAQ 12 6950 7950 10600 12600 13750 17450 18550 20100
The 1987 CSX empl TTs did show ratings. As I recall an SD50 was rated 18000 tons eastward over the Magnolia Cutoff, where the eastward climb is about 0.1% compensated.
CSX didn't put tonnage ratings in the ETT. However, they did have tonnage ratings, both as head end power and as helper power (on territories when manned helpers were required). Note - CSX was not using DPU before I retired so I am unfamiliar with how they are rating units use in DPU service.
WEVERN WCUMB1 BA 79 BA 109 2800 3200 4300 5100 5550 7050 7500 8150
CUMBOY BRUNSY BA 105 BA 76 3950 4500 6000 7150 7800 9900 10500 11400
CUMBOY CUMBED BA 105 BA 178 4600 5250 7000 8300 9100 11550 12250 13300
MILLR1 CUMBOY BA 115 BA 105 2900 3300 4400 5200 5700 7250 7700 8350
NORBRN MILLR1 BA 177 BA 115 9900 11250 15000 17850 19500 24750 26250 28500
MILLYL HAGEWM BAE107 BAS111 2500 2850 3800 4500 4900 6250 6650 7200
MILLMN HAGEWM BAS 34 BAS111 2500 2850 3800 4500 4900 6250 6650 7200
HIGHWM HAGEWM BAS 93 BAS111 2150 2450 3300 3900 4250 5400 5750 6250
HAGEWM MILLYL BAS111 BAE107 4600 5250 7000 8300 9100 11550 12250 13300
HAGEWM MILLMN BAS111 BAS 34 4600 5250 7000 8300 9100 11550 12250 13300
HAGEWM PORTWM BAS111 BAS 49 1500 1700 2300 2700 2950 3750 4000 4350
HAGEWM LURGWM BAS111 BAV 32 3300 3750 5000 5950 6500 8250 8750 9500
LURGWM HAGEWM BAV 32 BAS111 2200 2550 3400 4050 4400 5600 5950 6450
CUMYD2 CONPAY BF 179 BF 270 1350 1550 2100 2500 2700 3450 3650 3950
ROCKWA JOHNSA BF 227 BFC 45 1900 2150 2900 3450 3750 4750 5050 5500
CONPAY CUMYD2 BF 270 BF 179 1900 2150 2900 3450 3750 4750 5050 5500
CONPAY NEWCAY BF 270 BG 58 6900 7850 10500 12500 13650 17300 18350 19950
BRADDA FAIWVY BF 320 BS 302 1950 2250 3001 3550 3900 4950 5250 5700
GLEJUN EDGEPA BF 323 BG 53 1650 1900 2550 3000 3300 4200 4450 4800
GLEJUN WASPAA BF 323 BO 35 1350 1550 2100 2500 2700 3450 3650 3950
JOHNSA ROCKWA BFC 45 BF 227 1900 2150 2900 3450 3750 4750 5050 5500
CALLEN GLEJUN BG 25 BF 323 1900 2200 2950 3500 3800 4850 5150 5600
CALLEN NEWCAY BG 25 BG 58 5600 6400 8550 10150 11100 14100 14950 16200
EDGEPA CALLEN BG 53 BG 25 5600 6400 8550 10150 11100 14100 14950 16200
NEWCAY CONPAY BG 58 BF 270 5900 6750 9000 10700 11700 14850 15750 17100
NEWCAY WILLAE BG 58 BG 204 4000 4550 6100 7250 7900 10050 10650 11550
STERLN NEWCAY BG 155 BG 58 3150 3600 4800 5700 6200 7900 8400 9100
WASPAA GLEJUN BO 35 BF 323 1350 1550 2100 2500 2700 3450 3650 3950
FAIWVY BRADDA BS 302 BF 320 1950 2250 3001 3550 3900 4950 5250 5700
FEDONZ BROWPA BTC 6 PLM 61 1950 2250 3001 3550 3900 4950 5250 5700
ASHTAB CONNEA PLC 1 QD 115 4350 4950 6650 7900 8600 10950 11600 12600
ASHTAB PAINSV PLC 1 QD 153 4350 4950 6650 7900 8600 10950 11600 12600
BROWPA FEDONZ PLM 61 BTC 6 5900 6750 9000 10700 11700 14850 15750 17100
CONNEA ASHTAB QD 115 PLC 1 4350 4950 6650 7900 8600 10950 11600 12600
PAINSV ASHTAB QD 153 PLC 1 4350 4950 6650 7900 8600 10950 11600 12600
The above are the tonnage rating for portions of the CSX Baltimore Division and adjacent territory. The First 2 columns are mnemonics of the origin and destination of the particular rating. The next 2 columns are the assigned milepost designations for the origin and destination. The succeding columns are the ratings for each class of locomotive from 4 axle GP40's to 6 axle AC60CW's. I have lost the specific designation for each column of the ratings. Note, the ratings can and in many cases are different for different directions.
BigJimDo you really think that every engineer out there starts the cab before the engine?
Not sure I understand the question.
Even though we generally run 4-5 car trains (13 for Polar), I try to get the slack out before I notch out. But I'm not running 60+ car trains with significant slack between each car. As I noted, even having the floor underneath you go from zero to just walking speed in a split second could cause some balance issues.
BigJimWhy not? Ours were.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
BigJim tree68 All I know of that is what I've read. That explains a lot!Do you really think that every engineer out there starts the cab before the engine?
tree68 All I know of that is what I've read.
That explains a lot!Do you really think that every engineer out there starts the cab before the engine?
I have ridden in cabs a number of times - some starts were gentle, some were less than gentle - you soon learned where the welded rail was and wasn't. Depending upon the engineer and the train - the inroute slack action could be severe.
timzBy the way: the tonnage ratings in the timetable are just for show -- don't assume they're realistic.
timzDo they ever assign tonnage that the engine couldn't start,
tree68All I know of that is what I've read.
Gotta tell my Mom's story... when she was young (6 or 7) her family moved from Indiana to Kansas. Her Father and brother drove a truck with their belongings while her and her Mother took a train; they rode as paying passengers in a caboose of a freight train. (She said they saw her Father and brother waiting at grade crossings a couple of times on the trip. She waived, but they didn't see her.)
At one stop, she said she was up prancing around, trying to stomp on flies, which were thick in the caboose on the hot summer afternoon. A man in a dark blue suit came in the back door and told her, "Little girl, you'd better sit down." She said she had been told not to talk to strangers and she was not about to pay any attention to this man. "Who was he to tell me what to do!" She turned around to face the other end of the caboose and continued stomp at flies.
A moment later she heard some banging coming from the front of the train and she suddenly was sitting on the floor. She got up and sat next to her mother. But she had a hard time sitting still because her bottom hurt. She said that the man in the dark blue suit laughed at her, but she would not look at him.
I never thought to ask her if she was able to kill any flies stomping on them or in the act of suddenly sitting on the floor.
Semper Vaporo
Pkgs.
timz Do they ever assign tonnage that the engine couldn't start, if it happened to get stopped on the steepest upgrade? Dunno how often they do it now, but it used to be common on UP coal trains east from Cheyenne. The climb is 2.7 miles averaging 0.65% compensated, and a pair of SD40-2s would use momentum from the preceding downgrade to take 13000 tons over the top.
Do they ever assign tonnage that the engine couldn't start, if it happened to get stopped on the steepest upgrade? Dunno how often they do it now, but it used to be common on UP coal trains east from Cheyenne. The climb is 2.7 miles averaging 0.65% compensated, and a pair of SD40-2s would use momentum from the preceding downgrade to take 13000 tons over the top.
Offhand, I can think of at least two locations between Edmonton and Vancouver that have short westbound stretches of 0.6% or 0.7%. They are both on single track, so it is rare for a train to stop there, but some have stalled in the past.
Soon after this type of operation began, the 0.4 HPT AC-powered trains 'discovered' a bunch of new places where it is a bad idea to stop them in the rain.
I would go so far as to say that higher horsepower modern locomotives are getting back into the steam territory of being able to move a greater tonnage than they can start. Especially when it is raining or they are out of sand.
On that note, I have never used up a full sandbox's worth on one shift, but I have seen a number of locomotives run out enroute, or simply get released from the shop with no sand at all.
When starting a train and at low speeds, horsepower really doesn't matter as much as weight-on-drivers and wheelslip control. From experience switching with each of them, I think a SD40-2 would out-pull a SD60, Dash-8 or Dash-9, and be about equal to a SD70.
A 1800 HP GP9RM-slug pair will out pull any of the above at slow speeds, despite having less than half the HP. Why? It weighs more, and has two more traction motors.
timz When UP had ratings in the Spec Instr a few years ago, they said GP60s were good for 3400 tons on 1%.
When UP had ratings in the Spec Instr a few years ago, they said GP60s were good for 3400 tons on 1%.
Lol ok.
Maybe as long as the train kept moving above 30 mph, but we know how realistic that is.
By the way: the tonnage ratings in the timetable are just for show -- don't assume they're realistic. When UP had ratings in the Spec Instr a few years ago, they said GP60s were good for 3400 tons on 1%.
BigJim tree68 Starting from bunched, however, is one reason cabooses are gone. The last car in the train would suddenly go from zero to however fast the locomotive had gotten up to - often enough to knock crew members off their feet. A good engineer would gently pull out the slack until the rear notified him that the cab was moving.
tree68 Starting from bunched, however, is one reason cabooses are gone. The last car in the train would suddenly go from zero to however fast the locomotive had gotten up to - often enough to knock crew members off their feet.
A good engineer would gently pull out the slack until the rear notified him that the cab was moving.
If the floor under you goes from zero to even 5 MPH in an instant, you'll notice.
And recall that back in the day, there were no radios...
All I know of that is what I've read. And slack action, accidental or intentional, was a problem.
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