This will be an overview of different main track authority methods. It will not be exhaustive, just a general look at the different types of authority, what their key attributes are and some suggestions on modeling. I will break the authorities into 4 general groups:
I will generally be discussing the rules as I was taught, which would be those applicable in the US. There are many different rules books and rules have changed over the decades in response to new technology, better communication and attempts to improve safety. Because different railroads have different histories, different physical plants, different geography and different managements, the details of rules can vary between eras and railroads. The rules and operations I will discuss are generally applicable from roughly World War 1 to the 1980’s. The basic concepts though, cut across all railroads and all eras. Some basic concepts in 1870 rules books are still in 2019 rule books.
As such, consult the rule book appropriate to your era and railroad for specific details. I’m sure that anybody can find a rule book and rule that will conflict in the details with some of the things in this article.
Superiority of Trains
Most people would call these systems “timetable and train order” because those are the ways that superiority of trains are communicated. It was basic, fundamental method of operating trains from the mid 1800’s up until the 1980’s in North America.
The definition of superiority of trains is :
Trains are superior by right, class or direction. Class and direction are conferred by timetable, right is conferred by train order. Right is superior to class and direction, direction is superior between trains of the same class.
What that means is that a train order (“right”) is superior to a timetable schedule (class and direction), trains of the first class are superior to trains of the second, the second is superior to the third, etc. and that trains of class in the superior direction are superior to trains of the same class in the inferior direction. Armed with those understandings, its easy to operate by timetable. They set an orderly pecking order of who can go and who has to wait.
Regular trains are those listed in the timetable and extra trains are those who do not operate on a timetable schedule. Since they are not listed in the timetable, extras have no superiority by class or direction, they are inferior to every other train. They have no superiority by direction. Any superiority they might have is by right (train orders).
In most rule books, superiority of trains will be discussed in the 70 series rules. General movement of trains rules, will be in the 80-90 series. Rules covering movement by train orders will be in the 200-220 series of rules, and usually followed by examples of the forms of train orders.
A schedule is a powerful thing. It exists (unless annulled) whether or not a train is using it. A train operating on a schedule may not depart a station prior to the time listed in schedule and an opposing inferior train has to be in the clear of the scheduled time, regardless of how late the regular train is (or even if its running yet).
Under superiority of trains (TT&TO), when a train wants to leave a station it has to ask itself a series of questions.
- Are there any train orders that restrict my rights or give another train rights over me?
- Have I been given rights over another train?
- What class am I and are there any superior schedules do I have to clear?
- Am I in the superior direction? (regular trains)
The answers will tell it whether or not it can leave.
Timetable operation is well suited for a layout that has a main line run, operates a very small number of trains at any given time, there are gaps between the trains, the trains are very consistent and can run on time or close to it.
Movement by Train Orders
Train order rules can be very confusing because there are a lot of contingencies that real railroads contend with that aren’t really an issue on a model railroad. For example there are rules to cover communication failures, rules to cover issuing to superior trains first (the X response), rules covering orders that can be delivered vs. orders that have to be signed for (Form 19 vs. Form 31 orders). For a real railroad, all of these things are critical safety concerns. For a model railroad, not so much. Therefore I will skip over some of those topics in a beginner discussion.
Train orders are addressed to those that will execute them. They must be given to all the trains addressed in the same wording. If you give X123E train order #7 reading “Extra 123 East meet Extra 234 West at Bess”, then it’s out of form to give X234W a copy of train order #7 reading “Extra 234 West meet Extra 123 East at Bess”. Orders should be brief and not repetitive. Addressing an order to “All westward trains” is redundant, addressing it to “Westward trains” is brief.
The term “form” is used in two different contexts in train orders. There is a form 19 and 31 which concerns the actual blank paper form on which the train order is written. That is not the type of form in this discussion. There are different “forms” of train orders, proper wordings that do different things and have different meanings. Each train order form has specific wording. I would suggest getting a rule book for your railroad and era to see which train order forms were used (not all railroads used all forms), what the wording was and what their meanings were. The train order forms are designated by letter.
For purposes of this discussion I will describe what I consider are the minimum train orders that can be used to operate a model railroad session. This assumes there is a timetable for the model railroad. I will not describe them in alphabetical order, but more in an order that they might be used.
- Form K Annuling a schedule : If you have a timetable with regular, scheduled trains then Form K that annuls a schedule would be useful. “Annul” is a railroad term similar to “cancel”. A schedule that is annulled is not longer in effect for the day its annulled from the place its annulled. It must be given to all trains that operate on the subdivision for 12 hours after the train is scheduled to operate.
- Form L annulling an order: Similar to Form K is Forms L that annuls an order. Once an order has been annulled it is no longer in effect. A copy of the Form L must be given to everyone addressed on the order being annulled.
- Form G Extra trains : A form G creates an extra train between two points/stations
- Form A train meets : A form A designates stations at which trains must meet.
With those 4 orders once can operate a railroad with TT&TO. There are two more orders that might be handy, that require a little more verbiage and thought to execute.
- Form S-C right over an opposing train : Very useful for handling multiple extras in the same direction, especially when combined with Form E waiting times
- Form E time orders : Can be used to tell a regular train to operate late (but NOT early) or tell a train to wait at stations until certain times.
One order that a lot of modelers like, but is greatly misused is Form H Work Extras. Work extras have a lot more implications than a lot of modelers realize. They allow a train to operate in both directions between two points, however the train must provide flag protection, unless relieved in the train order, whether its moving or stopped. I would suggest holding off on this order until you have the other ones down.
Clearances
Clearances are another frequently misunderstood part of train orders. A clearance a form addressed to a train that tells them how many orders they are as supposed to get at that station and lists the numbers of the orders they are to receive. There are some other variations, but for the beginner, that’s the essence. A clearance clears a train to pass and depart a station with a train order signal set at stop or, since a clearance is require at an initial station on a subdivision, at the initial station. A clearance conveys no authority in of itself. One way to think of it is as a “packing list” that lets the crew know what orders they should receive so they can check to make sure they got the right orders.
Registers
Registers are documents that are used to record when trains arrive or depart a station. They are normally only at major junction points and at the initial and final stations on a subdivision. Since a train may have to stop to fill out a register and definitely must stop to check a register, real railroads use as few as possible. A train can use a register to see if regular trains a have arrived, but can’t use a register to check if an extra train has arrived or departed unless the dispatcher issues a train order to allow it to do that (usually form V). Register are essential for real railroads, they are not as critical for most model railroads.
Using train orders
One of the key concepts of train orders that often gets lost and makes it different from all other forms of authority is that it grants all the authority a train needs right from the beginning. Every other form of authority, every other system grants authority in small increments. Much of people’s frustration with TT&TO is trying to use it like an incremental system. When a train is cleared from its initial terminal it has all the authority it needs to travel completely across the subdivision to the end of the subdivision or the final destination. Theoretically at any point in a session, once all the trains mentioned in orders have been cleared, the dispatcher could get up and walk away from the desk and every train cleared could run to destination. Trains might get delays and no new trains could be added but everything out there could run to destination.
When an extra is cleared it must have an order on every single opposing extra cleared. A dispatcher can’t run two opposing extras out and then decide where they will meet after they get further along. There has to be something (meets, right over with waits) right out of origin.
Another concept is that it is a planned system not a reactive system. Real TT&TO dispatchers are working hours in advance, lining things up. Most of the TT&TO dispatchers I have worked with preferred TT&TO to CTC and definitely TWC, because CTC and TWC were more work. On a good territory a dispatcher could issue his orders in the first hour or so of the shift, get everything set up and then not have to do anything other than OS’s for the next 3 or 4 hours. The problem with most model railroads is they are so jam packed with trains and things change so fast (or the operators think they have to change) that TT&TO is used in a reactive mode, which it wasn’t how it was designed.
Using TT&TO in some ways requires a leap of faith to let things play out and not to change the train orders every 10 minutes. The best layouts for TT&TO are those with a consistent operating plan and more over the road running than short turns.
Next : Superseding the Superiority of Trains