I remember I was chatting with a fellow down at the Roberts Bank intermodal facility and he was saying (if I remember correctly) that the longest train they ever ran out of “the bank” was about 14000ft… (It was a CN intermodal)
Then I got chatting with my uncle and he was saying that I must have the number wrong because the drawbars and couplers wouldn’t be able to take that kind of strain.
… I thought it would be possible…but really wasn’t sure, so here I am.
What kind of limits do the draw bars and couplers have on them, assuming you had all the power necessary how long of a train could you build?
What other factors limits the lengths of trains… I know charging the air system would probably be another issue…
Can you make the train longer if it’s made up of a bunch of 5 packs instead of a whole bunch more singles?
This is a very good question now you’ve got me thinking. . . … … … I never thought their was a length limit. Anyway I’ve seen trains that were two miles long before. Once was on the CP on Kicking Horse Pass it had 3 AC6000CWs with two in front and one in the middle. So. . . it had 18,000 total Hp and two miles of mainifest freight. It was pretty kewl. I don’t know how much stress that was put on the poor knuckles though, I would imagine it to be alot. Dats all I know. . . … … .
On CSX the nominal maximum train length is 9000 feet, except on the old New York Central Water level route where intermodal trains up to 14000 feet are permitted.
On certain of the old Seaboard, ACL and L&N territories trains can be restricted to a maximum of 6200 feet account of the siding configurations on the mostly single track subdivisions.
Drawbar strain is more dependent on grades and tonnage than it is on train length. The rule of thumb on CSX is the maximum tonnage for a train is the tonnage that 4 SD40 locomotives rate over a territory ie. SD40 is rated for 2500 tons over a territory, the max train tonnage, without a helper, is 10000 tons. Adding helpers to the rear of trains changes the ‘trailing tonnage’ and trains that exceed the tonnage of 4 SD40’s can be handled with a rear end helper. CSX as a norm does not use Distributed Power locomotives, the helper territories are too short to the necessary benefits from Distrubuted Power. The 4 SD40 calculation applies to bulk commodity trains only as the cars in these types of service are normally fitted with high strength draft gear and coupler assemblies as well as high strength knuckles.
Merchandise trains have a maximum of what 5 GP40’s can haul over the ruling grade of the terrirory. Where an SD40 is rated for 2500 tons, a GP40 may be rated for 1800 tons, thus the Merchandise type train is resticed to 9000 tons. General service freight cars do not routinely get constructed with the ‘high strength’ components.
There is a picture I saw of a 200 car train through Deshler, with only 2 AC6000CW. I don’t know where it originated but I would imagine that a lot were either single stacked and empties. I doubt UP and BNSF could do something like this because of the grades through the mountains (if heading that way of course). I don’t know what kind of grades are on the route to New York but the real long ones tend to come from their. However, there is one train that uses the Sand Patch route that was well over 10,000 feet and only 3 engines (railpictures.net). I would be interested to know what happens through there.
All of my previous thoughts were that it was purely based on siding length, I had not really considered equipment strain.
I am used to coal drags through here that are all about 125 cars in length and I always just assumed that the length was limited by the sidings and number of cars that a particular power facility could accommodate.
Thanks to this question and answers, I not only learned something, but corrected a poor misconseption. Thank you to all that answered.
I’ll second what Mark pointed out, with distributed power you are only limited by siding length. We came accross this when we were trying to figure out ways to make RoadRailer and RailRunner trains more profitable. Although both are limited to about 125 units behind the lead locomotive, with DPU we could increase the number of revenue units to the siding length of the target railroad of 9,000’ to 162 units, about a 25% increase in revenue loads. That 25% can make the difference between loss and profit for a potential client.
When I was watching IC/ICG in the early 70’s, most of the coal drags on their double track main ran around 90 cars. I do recall seeing a returning (southbound) empty one night that was apparently two such drags combined, nearly 200 hoppers behind two Geeps. They were struggling on the long uphill into Rantoul.
Intermodal trains tend to be rather light per foot of train length, so, on low-grade routes, you can have some really LOOONG trains without getting near the drawbar limits. Two mile long trains are not all that rare.
In reply to a question that was asked way earlier, the couplers are rated at 390,000 pounds. There is a little reserve figured in, but if there are any stress fractures they could break at a lower loading.
390,000# would be grade E couplers/knuckles common only on unit train equipment. Figure more on 250,000 # for garden variety freight equipment (grade C). …which is why you don’t see more than 2 AC units on the head end of most freight trains.
I agree about the terminals. When coal unit trains first got started in the 1970s on the C&NW the coal department was concerned that the trains would not stay together as a unit. Therefore, the trains off the UP to Oak Creek, WI were designed to be long enough so no one in their right mind would take one into beautiful Proviso for processing.
Yes, the reference I found listed Grade C at 250,000 to 280,000 lbs but also refered to them as “Pre 1970” so I thought they would have all been replaced with the newer stronger Grade E couplers by now. But, considering the age of some of the rolling stock I can understand that they haven’t been!
I was chatting with a fellow from the CP, the CP runs a bunch of unit coal trains from Roberts Bank out to the coal basin in South Eastern BC, they run them back and forth 24/7… the trains are always in the 'round 'bouts of 115 - 120 or so coal cars always with an AC4400 on either end of the train.
Anyway, because CP and CN do directional running in the Fraser Canyon, and there’s no passing CP has wanted to double all the coal trains up from Roberts Bank to Kamloops, and run them as 230 car trains with an AC4400 on the front, two in the middle and one on the end, then when the train gets to Kamloops just split it back into two trains again and continue on.
It would be awsome to see, but apparently (and understandably so) the Union has been fighting it.
A Mark stated, the KCS was a tonnage RR. Back in the early 80’s, I used to do a lot of dove hunting along the line between Baton Rouge and Alexandria, LA. They ran long trains. I remember them running through there a nd you would sit for a while at a crossing. Present day, I do not see that long of trains. I go to our plant along the KCS line in New Roads LA, about 20 mile north of Baton Rouge. I can usually catch a couple of trains. I have noticed them to be quite a bit shorter and usually have a TOFC or container block attached to the end.
The Granddaddy of tonnage trains was the CGW. They would do yard clearers, 7 or more engines on the front and 200+ cars behind them.
Another was the GM&O across Alabama, Mississippi, and into Memphis. They ran 200+ trains all the time.
The N&W and C&O ran 200+ car coal trains out of the Ohio River valley to the Columbus and other points.
