Do the railroads run bidirectional on both tracks (wrong rail) on double track mains, or do they use strictly directional running of trains?
Timetables and books of rules will indicate how each track is used by each segment. Multi track will be indicated there as to whether it is one way or bi-directional. Bi-directional track or tracks will usually be signaled for both directions and so indicated. Otherwise a track may also be used by Form D’s (used to be train orders), or special bulletins (with Form D’s and special instructions. Most importantly the first rule of safety is to expect a train on any track and any time in any direction.
I don’t know what kind of official answer you might get from those that actually run the trains, but from my watching a U.P. double track main, I’d say they run trains in any direction on any track that is needed at the moment.
I guess I would say that a double track main is just a continuous set of passing sidings so fast or important trains can get around slower, stalled, or local trains, as necessary. Trains may or may not switch over to the other main at any set of crossovers. Just so long as they don’t run into each other head-on.
While individual tracks on multiple track territory may be signaled for operations in both directions, it is important to remember that most double track territories today that were double track ‘yesterday’ had current of traffic signaling ‘yesterday’. With the tracks having been signaled for current of traffic operations, all the industrial spurs and other track facilities were set up for that form of operation. When the tracks obtained signaling in both directions, the industrial spurs and other track facilities were not changed. This gets highlighted when a train has mechanical issues and must set out a car and it is on the track that ‘yesterday’ was against the current of traffic - none of the spurs have switches that open in the proper direction to make the set off.
In the old days there were many double track lines that were current of direction, i.e. one track for each direction and signaled for such. As the number of trains became reduced, many of these lines were converted to single track CTC. As traffic increased in recent times, many of those lines that had enough traffic to retain double track, have had to be bi-directionally signaled for flexibility and capacity.
Edit: Before I could get my comment posted, the above post came out, so please excuse any repetition.
The following will give you, caldreamer, a technical perspective on your inquiry.
Looking southbound, at the north slope of Tehachapi Pass in California, with Automatic Block Signals (ABS) with each track (of “double-track”) signaled in only one direction. The opposite track is signaled in the other direction.
That arrangement and signals were on borrowed time on the Tehachapi area (above photo), for bidirectional “two-track” CTC territory was coming: The below photo was shot from the same location as the above photo was.
Two-tracks are often misidentified as “double-track,” but now you know what the industry professionals and the railroaders call the lines. Hopefully, this technical aspect will have answered your question and be enlightening to you.
As other posters have said, with two (or more) track operation, each track is signaled for traffic in both directions, and the dispatcher controls the movement of the trains. When traveling on such track, it is possible to note that from time to time your train is moved from one track to another–and it is protected by the proper signals no matter which track it is on.
In double track (each track is signaled for traffic in only one direction) territory, it is rare that a train would move against the current of traffic–and if orders direct such a move, the train may travel no faster than it may when there is no signal protection. In such territory when a faster train would be overtaking a slower train at a point at which there is no pass track but a crossover between the two tracks the slower train would, on orders from the dispatcher, back over to the “wrong main” (the crossover switches would be trailing point switches), and the signals in advance of the crossover would go to stop, for the switches would be interlocked with the signal system. (I have seen such a move, and I expedited the move by, with the freight conductor’s permission, lining the crossover switches (ground throw) back and locking them once the freight was back on the right main; the conductor told the fireman I would line them back, and he and the rear brakeman simply swung on when the caboose reached them).
In remotely controlled multi-track territory, the dispatcher controls the switches, and the engineer follows the signal indications.
Traditional double track is defined as involving a “current of traffic” on each of two tracks. Two main tracks is the correct term for two tracks signaled for movement in both directions. In the employee time table double track is indicated by “DT” while two main tracks is “2 MT”. While both involve two tracks, they are very different operations.
Mac
Many years ago I rode the Capital Limited out of Chicago and we ran on the left side from Hammond Indiana to Cleveland Ohio. Reason was twofold. Nearly all freights and we passed at least ten enter the yard at Elkhart on the south side of the tracks and we entered what was left of the Toledo station trackage on the north side. Another example is at Indianapolis where westbound trains cross to the eastbound main at Union station so they can enter the yard west of town.
The timetable will designate the method of operation.
If the operation is “double track”, Rule 251 or Rule 9.14 (GCOR) then its current of traffic in one direction, signaled in one direction on each track.
If the operation is CTC, “two main tracks” (2MT), rule 261, then its signaled and operated in both directions on both tracks.
Double track is a very high capacity system, until something goes wrong or you want to do something other than run with the current of traffic. Then its not that flexible.
CTC is more work to operate but is many times more flexible than double track.
Railroads have been retiring the double track and replacing it with CTC over the last several decades.
With modern 2 Main Tracks, the ‘primary’ direction of running on the various segments of each track is at the discretion and control of the Dispatcher. By a few computer commands, the dominant directions can be changed from the typical 1 track each way, ‘right-hand’ running, to both tracks in the same direction (either way), or even a ‘left-hand’ running scheme (still 1 track each way). Note that the set-up can be changed every few miles to accommodate either the configuration of the tracks (as BaltACD pointed out above), the demands of the traffic (commuter trains with frequent stops at certain station platforms on a particular side of a specific track) in the midst of freight trains - see Carl Shaver’s “Trackside Lounge” thread and other posts here for frequent descriptions of that, or just the sheer volume and speeds of the traffic in each direction.
There are also ‘paired track’ arrangements, where each track is separated by a few miles, but operated as if they were either Double Track (1-track each way), or 2 Main Tracks (each track bi-directional). The difference here is that because the tracks are so far apart, there are few (if any) ‘cross-over’ type connections between them.
[:-,] Then there are the cooperative “shared paired track” (I think I just invented that term ! [swg] ) arrangements between 2 different railroads (might have been merged since then). The ones I’m thinking about now are CN and CP in the Parry Sound, Ontario and Fraser River, British Columbia areas, as well as the former SP and WP in the western deserts (additions, clarifications, and corrections invited !). The weird thing about these - at least for the Canadian roads - is that their single-track lines were each necessarily signaled for bi-directional running before that arrangemen
Going into or out of Chicago on the California Zephyr or Southwest Chief can be interesting (three tracks between Chicago and Aurora) as you watch the movements of the Metra trains going in the same direction you are traveling–you may well find that your train is moved from one track to another as the dispatcher keeps the trains moving
Paul, I have traveled east and west over the Ontario portion of the Canadian paired track and west over the British Columbia portion–but I do not remember noting if the block signals for what is now the “wrong” direction are still in use. I plan to take the Canadian to Edmonton and back in September; I will try learn if they are, though I will probably sleep through most of the BC portion.
As to the Nevada arrangement, the timetables indicate only one direction for each of the segments. So, I imagine that any traffic in the opposite direction operates under dark territory rules.
One thing that many overlook. In double track (either kind of signaling) not all rail facilities can be used from either track. Trains that have station work at those facilities must be on the correct track to perform this work; in most cases trains in different directions cannot work that facility at the same time because of this. Part of the Dispatching function is to have trains on the proper tracks to perform their station work. (Note - Station work can be picking up or discharging passenger, picking up or setting off freight cars)
The restrictive nature of Station Work is what creates the biggest obstacles in keeping a particular subdivision operationally fluid; especially when freight and passenger need to use the same track segment at the same time - somebody has to wait (and that wait will occupy another track segment - which may affect the needs of other trains etc. etc. etc.)
Now to really complicate matters. The NEC from NYP - PHL is mostly 2 MT, 3 MT, & 4 MT (few miles 5 & 6 ). Before Amtrak had such a increase of traffic 4 track territory had the 2 middle tracks bi-directional MT and the outside 2 tracks were signaled RH current of traffic movements. As far as can be determined all tracks on that segment are now bi-directional MT. South of PHL to WASH had a mixture of set ups. Some 4 track full bi-directional, 4 track with 2 middle bi-directional, 3 track bi directional 3 track center track only bi-directional, & 2 track bi-directional MT.
All these configurations have been slowly change to all MT bi-directional. Only ETTs can show present and past set ups. It may be all sections are now all MT bi-directional ?
It may be all MNRR tracks are multiple MT ? All sections of Amtrak New Haven - BOS that are signaled are bi- directional again only an ETT will tell.
KP probably has examples of this around LAX.
Deggesty
Yes the opposing direction signals are still operable on CN and also on CP in the BC directional running arrangement. There are occasions where because of slides or fires in the Canyon etc that each railway must be equipped to run trains in the opposing direction. The last time I recall this occurring was about three years or so ago when the CN bridge over the Fraser at Lytton, BC caught fire and had to be extensively repaired over a period of a week. It doesn’t happen often but it does occur.
Charlie
Chilliwack, BC