Double Drafts on the SS(Combined trainsets into one train?)

I was reading the "interesting South Side consists" thread, and I saw the video of the two trainsets coupled together running as one train, and I was wondering if both locomotives are providing power, or if only one is used to push the entire set? I know that on multiple unit lashups you can bring units on or offline, and sometimes you have one locomotive providing traction and another providing HEP, but what happens when two commuter rail trains are coupled up, putting one of the locomotives in the middle? Can both provide tractive power for the train at the same time?

Yes. I believe that there is a limit to how much the locomotives can push/pull and I am sure that an engine that's not providing tractive effort plus 12 coaches is more than what one locomotive can handle (these are GP40MCs and F40PHs, not GE locos)

i heard that they couple trains together like that for special Foxboro trips so if that's the case, I am sure that they will need two locos running to be strong enough to pull twelve coaches full of people.

I am sure that both of them were providing power. I don't think HEP is necessary since it was not a revenue run but an equipment move although one of them might have been providing it.

I remember in Lincoln when 466's equipment crapped out in South Acton, and 468 was supposed to bring their passengers and equipment in from S. Acton. This was a few years back and the offending engine was the 1115 and both were 5 car sets. So, the inbound comes in like this: 1647-flat-flat-flat-flat-1137(working hard)-1640-flat-flat-flat-flat-1115 (hardly workin').

The 1137 was providing traction and HEP, and 1115 was completely shut down.

Sounded like 1137's turbo was spooling up just like a freight train!

-Dan

Stmtrolleyguy wrote:I was reading the "interesting South Side consists" thread, and I saw the video of the two trainsets coupled together running as one train, and I was wondering if both locomotives are providing power, or if only one is used to push the entire set? I know that on multiple unit lashups you can bring units on or offline, and sometimes you have one locomotive providing traction and another providing HEP, but what happens when two commuter rail trains are coupled up, putting one of the locomotives in the middle? Can both provide tractive power for the train at the same time?

Well under nomral circumstacnes you would not see two trains coupled with 1 locmotive in the middle (double draft) unless 1 set is broken or the equipment is being moved... In any case 1 locomotive can tow its own train and a dead set if needed. If both locomotives are up and running then you would need an M.U cable for them to both work together and communicate. Also as far as the hep goes, if you have a screamer then when the main engine dies so does the HEP.. so unless your towing with an 1100 or F40PH-2C then I don't think that another screamer would be able to provide HEP to the dead set and its own if the two sets were coupled but I'm not 100% sure...

Someone told me here on these forums that for revenue trains the MBTA uses a max of 8 cars. Yet you guys are saying that our diesels can pull 12 car consists with HEP and tractive power? If so, why aren't we seeing 12 car consists on heavily travelled routes like Providence and Greenbush?

Veristek wrote:Someone told me here on these forums that for revenue trains the MBTA uses a max of 8 cars. Yet you guys are saying that our diesels can pull 12 car consists with HEP and tractive power? If so, why aren't we seeing 12 car consists on heavily travelled routes like Providence and Greenbush?

Running more then 8 cars over a long period of time would take its toll on the Loco's. Where there is a situation of a break down and you see 2 sets together the broken down set can sometimes power its own HEP, depending on why it broke down in the first place.

AEM7AC920 wrote:Well under nomral circumstacnes you would not see two trains coupled with 1 locmotive in the middle (double draft) unless 1 set is broken or the equipment is being moved... In any case 1 locomotive can tow its own train and a dead set if needed. If both locomotives are up and running then you would need an M.U cable for them to both work together and communicate. Also as far as the hep goes, if you have a screamer then when the main engine dies so does the HEP.. so unless your towing with an 1100 or F40PH-2C then I don't think that another screamer would be able to provide HEP to the dead set and its own if the two sets were coupled but I'm not 100% sure...

There are scheduled double draft trains on the South Side. Some which run in revenue service! They normally just tow the second train in, because they dont always have a MU cables.

The HEP runs separately since you would need another pair of 480v cables and those cables are hooked up by mechanical not transportation workers.

I have a manual of a Bombardier coach somewhere and it says in there the sets are designed to run up to a certain amount of cars. I forget what it is, but it's NOT 12 cars! It's either 8 or 10.

With old tired equipment there are a lot of variables, but most of these GP40/F40s can easily pull 12-13 car trains plus a dead engine, they just don't do too well making track speed over 50!

The most I have run are 13 cars, plus a dead engine, with 9-10 being K-cars, and I don't recall any problems, just a response like a freight train, and a lot more current. It is tough to brake these smoothly, with an engine in the midde of several cars, (with it's more powerful braking system), but the challenge is more in getting up to speed than slowing down.

Bill

Also, the stations are not designed to handle more than 8 cars. The most cars I've seen on a commuter train is 7 cars. Every time that they run 2 consists with one engine, it's going to take a few months off it's life span.

I have an old friend who used to work for the "T " when Amtrak ran it and I have had the chance to ride with him on the franklin line when they pick up the second draft and tow it to Boston. He reported to me that the only time they would use the second engine for anything other than air waas when it was snowing out or in the fall when there where a ;ot of leaves on the rails and they need the traction effort of the second engine to move the train. there was normally a mecanhic there to hook up every thing if that was the case.

diburning wrote:Also, the stations are not designed to handle more than 8 cars. The most cars I've seen on a commuter train is 7 cars. Every time that they run 2 consists with one engine, it's going to take a few months off it's life span.

I have seen 8 car revenue consists occasionally. Sometimes it would be 8 K cars, and other times it'd be 7 K cars with 1 flat. Mainly on the Providence or Worchester lines.

Did anyone see the question writen a while back to the MBTA GM??? I can't remember what the question was exactly but if I remember correctly I think he said that the T limits the consist to a maximum of 9 cars because of the ability of the locomotive... I've never seen a 9 car consist but according to the GM they are possible...

sery2831 wrote:

AEM7AC920 wrote:Well under nomral circumstacnes you would not see two trains coupled with 1 locmotive in the middle (double draft) unless 1 set is broken or the equipment is being moved... In any case 1 locomotive can tow its own train and a dead set if needed. If both locomotives are up and running then you would need an M.U cable for them to both work together and communicate. Also as far as the hep goes, if you have a screamer then when the main engine dies so does the HEP.. so unless your towing with an 1100 or F40PH-2C then I don't think that another screamer would be able to provide HEP to the dead set and its own if the two sets were coupled but I'm not 100% sure...

There are scheduled double draft trains on the South Side. Some which run in revenue service! They normally just tow the second train in, because they dont always have a MU cables.

The HEP runs separately since you would need another pair of 480v cables and those cables are hooked up by mechanical not transportation workers.

I have a manual of a Bombardier coach somewhere and it says in there the sets are designed to run up to a certain amount of cars. I forget what it is, but it's NOT 12 cars! It's either 8 or 10.

Thanks for the tip, I didn't know that the southside double draft consist was ran in revenue service!

AEM7AC920 wrote:Did anyone see the question writen a while back to the MBTA GM??? I can't remember what the question was exactly but if I remember correctly I think he said that the T limits the consist to a maximum of 9 cars because of the ability of the locomotive... I've never seen a 9 car consist but according to the GM they are possible...

Slightly off topic, but I heard that a couple transit agencies do run 10+ car consists with one loco I think. I've seen Youtube videos of NJT 10+ bi-levels in a single consist, and I've heard of GO Transit running 10 - 12 bi-levels in a revenue consist. I'm not sure if these extra-long consists are due to stronger diesels or electric locos or something?

A couple of videos shows 1 loco pushing 9 to 11 NJT bi-levels in revenue service.

http://www.youtube.com/watch?v=ak8_A9ZX6Fw

http://www.youtube.com/watch?v=NxXjC5R1a3k

http://www.youtube.com/watch?v=9oPA_3NPSlo

Here's a couple vid's of GO trains with 1 diesel loco powering at least 10 bi-levels minimum.

http://www.youtube.com/watch?v=9Uk3wjT1J-4

http://www.youtube.com/watch?v=U7OZh-tl-lc

If other agencies can run 10 - 11 car consists for revenue service, then the MBTA can, particularly on the Worchester and Providence lines.

Just because it's possible doesn't mean the T will do it. Try not to think like a railfan for a minute. If you're currently running 6/7-car trains, how can there possibly be demand to run 10-car trains? Let's make the math easy. Say you have 130 seats per car, and you're running seven cars. That means adding 3 more cars at 130 seats per car means there's 55 standees in each and every car of that 7-car train. I can say that I haven't been on the commuter rail up there in decades, but I know damn well that's not true. Besides, loading and disembarking with cars not hitting the platforms, as well as slow acceleration from a heavy train (as well as a diesel to boot; EMU's pick up much quicker), it would just make sense to run two five-car trains 15 minutes apart, or zone express them, if it's possible.

But if you really want to run longer trains on the Providence line with one engine, and you had a magic wand, go get an AEM-7 or ALP-44. Amtrak runs them up and down the corridor with eight cars all the time.