Modelling what might have been in southeast BC and northwest Wasington

NMRA 1965 Vancouver Convention Timetable

I ran across a copy of the timetable (program) from the 1965 NMRA National convention that was held in Vancouver, BC, Canada. I believe it was the first one outside of the US. I did not attend as I was just a bit too young.

I have scanned it into a PDF file and posted it in case anyone is interested. Note that the file is 41 MB in size.

Installing switch machines in staging

I have been working on the layout while we are self-isolating at home. The staging track yard ladder switches are made by Peco and have an internal over-centre spring to keep the points aligned. When I installed all of them way back when, I decided to just go with the intrinsic power routing that the switches provide, and that has worked well. However, I didn’t provide enough separate feeders to sections of the yard ladders which resulted in one needing to align switches way beyond were you are in order to get power. This has proven to be a continuing problem, especially for guest operators. 

I decided after VanRail to fix this problem, and after considering the overall situation where the power routing is dependant on the points, I decided to retrofit the switches with my usual powered frog solution using microswitches for reliability. This meant that all of the track switches would have to be lifted in order to drill the necessary holes for the point throw wires and to reconfigure their electrical connections, but in the end they will all be fully powered and operate exactly the same as the others around the layout. Brian helped lift the track a while back, but I never got around to installing anything until this week.

The first step was to prepare the toggle switches for the main throw mechanism, and then install them under the staging plywood.

Here are some of the switches after modification:

I now have all of the upper staging track switches back in place, and all but two of the switch machines installed under the plywood. My back will only let me do a few each day because there is very little room between the upper and lower staging decks. Working slow and steady, with constant checking has proven to get them installed and working correctly. They still need all of the microswitches for frog power routing, but that will come.

The switch machines for the lower staging yard are easier to install because I can get underneath the layout, but re-installing the track switches was a pain. With only 10” of separation between the levels, there is barely enough room for my head to be able to see to reconnect the rails and replace the track nails. What fun!

Relaxing role matching to cars during restaging

After a lot of thought and a bunch of playing around with the code and running many tests, I have come to the conclusion that trying to have a prioritized order to the car attributes will not work. The thought was that if we could figure out the right order from most important to least, then we could start to relax the matching specifications by first ignoring the least important one, and so on with increasing importance. This would help to “force” a close-enough match during restaging.

The main problem with this idea is that there is really no intrinsic relative importance to these attributes, so that we could ignore the attributes in a fixed sequence of increasing order of importance. Such an ordering does not exist in general, because what may be safely ignored in one situation might not be the same in another. For example, is the car owner more or less important than its length? I think the correct answer is “it depends…” We may have roles that must have CPR cars because there is a contract to supply them but they don’t care about the length, and we might have other roles that must have a certain car length to fit at a loading dock but don’t care who the owner is. Neither is always more important than the other. A better way is needed to indicate what is optional and what is not.

Here is what I came up with, at least for now. Taking car length as an example, currently the program will accept an input of blank or “*” to indicate “don’t care”, or a list of one or more specific items to indicate that any one of them is acceptable. For example, a role with a length specification of “*” means that any length car is acceptable. A specification of “40|50|60” means that a car length of 40, or 50, or 60 feet is acceptable, but nothing else.

I am proposing to extend this approach and allow for something like 40|50|*, which would mean either 40 or 50 feet to start, but if there is no match, then the length can be relaxed to “Any” for a subsequent attempt. Exactly how this would apply when there are multiple attributes that include an “*” is not clear to me yet, but I’m sure something will emerge. The issue is that if a role has say three attributes that all can be relaxed, which one (or more) do you try first? How many attempts do you try? What order do you relax them in? As a start to implement the basic idea of being able to make some attributes optional, I will just have it be all or nothing. The first pass should match exactly or not, and a second pass will simply ignore all of the “relaxable” attributes.  Maybe we should call them “Optional” attributes if they include an “*”?

The end result is that each role can include some specifications that are not optional and must be matched (they don’t include an “*”), and some that are optional and may be ignored in order to keep the cars rolling. I think this should provide enough flexibility, at least for now.

Car attribute priorities

Some thoughts on the relative importance of various car attributes that can be considered when restaging cars.

The issue came to light during a phone call I had with Colin about his waybills and how he selects them for a particular car. I need to try to duplicate the mental process he goes through when resetting the layout, if at all possible.

At the moment, I have identified the following attributes, or characteristics, of a car that can be used when selecting a new role for them in staging. The list now includes the reporting mark initials and number, plus the owner railroad. I have listed them in a suggested order of most important to least to be considered when matching a car to a role, along with one sample for each attribute. Note that not all attributes will apply to one specific car. Most obvious is a gallon capacity for a boxcar. But, they are all available to be used as appropriate. 

  • – Initials: CP
  • – Number: 123456
  • – Type: Box
  • – Length: 40
  • – Subtype: Insulated
  • – Class: Rough
  • – Door: 8 feet
  • – Capacity: 6000 gals
  • – Owner: CPR

The order of these has some significance when we consider what to do when there is no match. The current program can handle a sequence of either-or values so that more than one attribute value can be considered to be a match. For example, the car length spec can be shown as “40|50” which means either a 40 foot or 50 foot car is acceptable and will match the role.

But what happens if no roles match a car that needs to be restaged when using this approach? Colin said that he often has to “substitute” cars for waybills so that the car can remain on the layout and have a role to play. We obviously want this substitution to be as close a match as possible, and as an example we will readily substitute a 6 foot door for an 8 foot request, as that will be barely noticeable. However, substituting a tank car for a box car would not be a good idea! So obviously some of the different attributes have more importance than others, with the primary car type being very important.

My idea for the program is that if a match can’t be made, then a second pass will be made, this time ignoring one of the less important attributes. If still no match, then we repeat this process until we have gone as far with substitutions as we are willing, and give up and store the car. It is this ordering of importance that I am trying to figure out.

Role selection without sufficient suitable cars

My process to restage cars in staging by finding a role for each car relies on being able to find at least one suitable role for each car that is restaged. If no role can be found the car must be removed temporarily to storage. This approach works well when there are enough suitable roles to select from for a given car, but it breaks down when there are not. Too many cars may end up in storage when the entire point of the exercise is to run trains! A solution to keep cars moving is to substitute roles that are not a perfect match and carry on. Colin mentioned that he and Gary often have to do just that when using their traditional paper car card and waybill system. I’d like to capture some of the ideas behind how this “forced” matching is worked out and implement it in the program.

There are obvious things we can do in some cases. For example, if the particular car to be restaged has 6 foot doors but there are no roles asking for a 6 foot door, only 8 foot, then we may decide to send the car anyway, even though its door is narrower than what is requested and a real shipper would be angry because their forklift truck would not fit. The basic notion here is that there may be some parts of the car spec that can get ignored to help find a match, without causing too much grief. In this case we ignored the door attribute because it really doesn’t matter, nothing will actually be loaded. Maybe there is an order of things that we can ignore in the hope of finding a match so that the car does not have to get pulled off into storage. For example, if we don’t find a match to start, first ignore the door spec, if still no match, then ignore the car class, and so on until we run out of things we are willing to compromise on and the car has to be moved to storage. I suspect that people go through something like this in their minds when selecting paper waybills. I’d like to try to capture that in some simple rules that I can implement in the program.

Role “Legs”

In addition to the Car Specification, a role also defines where the car goes on the layout to fulfil the role. Each of these segments of the car’s journey are currently called a “Leg”. This probably needs a better name, but it will do for now.

A leg includes the type of car bill, the destination track, the load, and the wait time after arrival for loading or unloading, or whatever.

Typical types of car bills are “Empty Supply”, “Freight Waybill”, “Empty Return”, and so on. I call them all “waybills” even though that is not technically correct, but so be it.

Loads will normally be specified only for the freight leg of the journey, but it can be anything that makes sense to the user. A car could be used to deliver one load and back-haul a different load.

The notion of legs can easily be expanded beyond the typical waybills to include extra car moves such as for icing, cleaning, custom’s inspection, and so forth. There can be any number of legs in a role. Each leg also includes the wait time that a car must remain at its destination before being eligible to move again. Usually this is about a day, but could be as short as a couple of hours for icing, etc. Again, it depeneds on the desired effect.

To help visualize all of this, here are a couple of example roles, expressed in English:

Role One:
– Suitable for a Boxcar, 40 feet, Rough, with 8 foot doors, at CPR Staging.

Legs:
– Empty Supply to Shipper A;
– Freight Shipment of Lumber to Receiver B;
– Empty Return to CPR Staging.

Role Two:
– Suitable for a Boxcar, any length, Clean, any width doors, at GN Staging.

Legs:
– Freight Shipment of Appliances to Receiver C;
– Empty Return to GN Staging.

Roles also include a weighting, or a kind of priority, that is used to influence the random selection from all suitable roles. Roles with a higher weighting will have more chance to be selected, while roles that should only be picked on occasion should have much lower weights.

There are all sorts of ways that this concept could be improved going forward. I can see having some of the legs optional with some sort of probability, so as to reduce repetition and boredom. And, it might be possible to have roles that are continuous for cars in captive service that just go back and forth between two locations. Lots to think about.

Roles and car specifications

Ok, so now we have a bunch of attributes that describe a car, but how do we use this when restaging cars? The things that will make use of all of this car attribute stuff are called “Roles”. A Role includes basic shipment information, but it also contains the entire life-cycle of a car from staging, on to the layout, and eventually back to staging. Some of the phases of that life-cycle have the car being moved empty for supply or return, so there really is no shipment for those parts, hence the new name “Role”. Roles now replace the earlier primitive shipment model that made too many assumptions and caused a lot of grief.

Every car in staging that is about to return on to the layout requires a role that governs all of the places that car will go. For every car being restaged, the program searches through all of the available roles to find those that are suitable for that car by considering all of its attributes. Roles contain a Car Specification that gets tested for a match to the car. A very simple example role might say that it wants a “Boxcar:40” and is silent on the other attributes, so they are considered as “don’t cares”, and only the Car Type and Nominal Length of the Car will be considered. In this case, every 40 foot box car waiting to be restaged would be a match.

This is all part of the process that we go through manually with paper Car Cards and Waybill systems during restaging, I just want to capture the essence of the process and automate it.

Roles usually specify a car type and a couple of the other attributes, but the process of matching cars to roles can get quite complex when we start to think about more subtle issues. What if a shipper can accept cars of different lengths, but not just any length, say 40 or 50 foot, but no longer. And how do we handle roles that apply only to specific individual cars and no others, even if they share the same attributes? A good example of this would be captive service between two industries. And of course there is the owner railroad, and reporting marks to consider. The combinations can grow to be quite complex in order to handle all of these special cases, but we still want the system to be easy to define for the much more common simple cases without becoming so complex that it is hard to understand.

This sounds like it is getting very complicated to set up the data, but please remember that all of these fields can be left blank or filled with just an asterisk (*) and they will not be considered during selection. Only a few of the fields will be routinely used, such as Car Type and Nominal Length. 

My solution is to use a series of “Specifications” that each contain a description of which car attributes are “acceptable” to the Role for that piece. The combination of all of these specs is referred to as the Car Specification. So, what is a specification? In simple terms it holds zero or more car attributes that can be matched to a specific car to see if they match or not. The whole notion of a “match” is non-trivial, as we must handle multiple acceptable values, an empty list that signifies that we don’t care about that particular car attribute, and cars that have empty attributes.

Some examples should help makes this clearer. Let’s consider a car’s nominal length. If an industry can accept only 40 foot cars due to loading dock spacing, that would be specified simply as “40”. If it can handle 40 or 50, but no other lengths, it would be specified as “40|50”, where the “|” (vertical bar) signifies “either”. A specification list can hold as many alternatives as needed. In this case, when the role is being considered for a particular car being restaged, it will be included as a possible candidate for any car with a length of 40 or 50 feet. Other actions will affect which role finally gets selected, but it first must be a candidate role that matches the car. The overall selection process does this matching for all non-empty specifications.

On the other hand, if we don’t care about the length of the car, for say a team track, then the specification becomes a simple asterisk, “*”, meaning “don’t care”, and the role will match any car length.

A more complete example would be for a Boxcar, 40 or 50 foot, Clean or High class, with 6 or 8 foot Doors, but we don’t care about a Subtype, or a Capacity. The car specification for this would be:

Box:40|50:*:Clean|High:D6|D8:*

The complete specification will also include more don’t cares for the initials, number, and owner railroad, but these have not been added in yet.

Ordering car attributes

Given that we now have six attributes to describe a car, we need to decide on a typical order for them when they get displayed. Some are more often used, like the main Car Type, and some are less frequently used, such as Door style. I am thinking that we want them to be arranged from left to right in decreasing order of usage. So here is what I came up with:

Type : NomLength : SubType : Class : Door : Capacity

Those that are blank will simply not be included. Examples again from Colin’s railroad:

  • Boxcar:40:H:D8
  • Autorack:85:2 Deck
  • Tank:40:Vinegar
  • Tank:40:Oil:8000

And one with everything, just not sure what it all means together:

  • Boxcar:40:Insulated:H:D8:6000

More thinking about optional car attributes

I started to think more about the car attributes and which ones are really necessary. I had said that we need the Car Type and Nominal Length, but not always the other four attributes. Now I am thinking that they are all optional. Stay with me for a moment, and it may make sense. Ok, we do need the Car ID, namely the Road and Number, otherwise we can’t find the car to move, and we need the actual length to make sure there is space for it. But as for the other things, they are only used to select suitable shipments for the cars when they get restaged. It would work even if we had all six attributes blank, meaning “don’t care”, or “unknown” for everything. That means that such a car could be given any role, as there is nothing to match on. While this sounds silly, it is a good way to get a new system started by generating lots of car movements without any real regard to what is going where and in what type of car. Not very prototypical for sure, but it can help prove out a train scheduling scheme and get lots of cars moving about. There is nothing really that dictates that only one specific type or class of car can be delivered to a certain industry. It is all 4’- 8 1/2” between the rails and any car can physically go anywhere. After some experience is gained with how the cars move with the trains according to their timetables, more specific roles and car types can be introduced to narrow things down and get more prototypical movements.