Car Routing

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Car routing, or determining how cars move from point A to point B, is the most important job a Yard Master has.

Train Symbols and Routes (TSARs)

Much like the Russian Czars of old, TSARs rule the FYM world. If it is not on a TSAR is didn't (shouldn't) happen.

See Train Symbols and Routes (TSARs) for more information about TSARs.

The first thing to do when trying to learn how traffic is handled in your yard is to read the TSARs that pass through your yard. All of them. Notes specifically for your yard will (most of the time) have @@[Yard #] - [Name] in the TSAR notes. When reviewing the TSARS for your yard you want to look for the following:

  • "works here", "work as needed", or some variant - This typically indicates that you should pull off any cars for the local industries in your yard. This may also mean that you can add cars for destinations down the line to this train.
  • "setout" - This typically indicates that you are to pull a block of cars off this train for inclusion on a different train passing through later.
  • "pickup" - This typically indicates that you are to add cars from an earlier setout.
  • "check engines" or "fuel power" - If you have fueling facilities in your yard you should refuel the engine if they are below about 500 miles left.

TSARs may also contain information about how many and what type of engines should be used for a train and the types and number of cars for unit trains.


Local trains form the start or end of a car's journey from source to destination and often traverse very short distances. Locals carry cars from larger sorting yards to smaller yards for delivery to local industries and then back to the sorting yard. In some cases this may lead to a situation where cars will travel through your yard to the sorting yard and then come back to your yard on a local train.

When reviewing TSARs make sure you have a good understanding of locals that run to and from your yards.


As soon as a car needs to move from an origin served by one railroad to a destination served by another, it will need to be interchanged or transferred between railroads. A car will need to be interchanged more than once if there is no direct connection between its origin and destination railroads. For example, a car travelling from an origin on the Florida East Coast railroad to a destination in California served by BNSF cannot be transferred directly between those railroads - the FEC only has lines in Florida, while BNSF does not get any further east than Birmingham, AL. Instead, the FEC interchanges directly with NS or CSX, either of which can transport the car to a suitable interchange point for BNSF.

In real life, almost all cars are eligible for interchange, regardless of their owner (railroads, railroad pools, or private owner); FYM assumes that all cars are eligible to travel to any destination.

Interchange can be completed in several ways, depending on the location and volume of traffic:

  • Cars can be left at an interchange siding or yard at a junction between two railroads, and later collected by the other railroad.
  • A transfer train may travel directly between yards of the two corresponding railroads, avoiding the delay and capacity constraints of interchange tracks.
  • A terminal railroad can act as an intermediary, receiving cars from one railroad and transferring to another (e.g. the BRC or IHB in Chicago, or TRRA in St Louis). These are often jointly owned by larger railroads.
  • A run-through train can proceed directly from one railroad to another, with its destination being some way beyond the interchange location. Unit trains many continue from origin to destination without even stopping to change locomotives, to further streamline the process.

While it is reasonably common for Class I railroads to allow their locomotives to travel on other railroads (repaid by railroad B's locomotives being used by railroad A in return, or otherwise by monetary compensation), it is very uncommon for the smaller Class II or III railroads to allow their locomotives to travel any further than necessary, as they lack the resources to continue operations without those locomotives.

In general, a railroad will avoid transferring cars to another railroad needlessly early, as a shorter route will reduce the fees they can charge - this is particularly relevant for rival railroads serving the same area, such as CSX/NS, or BNSF/KCS/UP. However, railroads will not resort to ridiculously roundabout routings via small branchlines - these lines lack the capacity to handle any significant amounts of interchange, and it would be extremely costly to use such routes unnecessarily. For railroads that are not highly competitive with one another, interchange routings are typically agreed to make best use of high capacity lines and yards, and to avoid highly unbalanced car flows (i.e. many cars arriving via one route, but returning via another).

Reciprocal Switching

In many major cities, and other areas served by multiple railroads, an industry is able to route cars via more than one railroad, even if cars are only delivered by a single railroad. This arrangement is referred to as reciprocal switching, as the arrangement often allows both railroads to equally access one another's customers in a reciprocal fashion. In FYM, this is represented by an industry being covered by multiple map IDs, one for each railroad involved. In these cases, all railroads have equal access - one railroad can interchange cars for the customer to the terminating railroad, and the customer can decide which railroad will take the car away to its final destination. Not all industries within a given area will necessarily be covered by reciprocal switching arrangements; these are often complex and can be based on what railroads historically served a customer, forced upon railroads during mergers to encourage competition, or negotiated by a major new customer.

A notably large example of this sort of arrangement are the Conrail areas in MI, NJ, and PA, which are given the railroad IDs CRMI, CRNJ, and CRSJ (South NJ/PA) in FYM. Following the joint purchase of Conrail by CSXT and NS, these locations were kept as joint service areas, with both railroads contributing to servicing these customers. As such, cars to and from any of the CRxx railroad destinations can be routed via either CSXT or NS.

Reciprocal Switching Database & Terminology

The Serving Carrier Reciprocal Switch (SCRS) tool provides detailed information, customer by customer for all railroads, of reciprocal switching status.

Some railroads have made SCRS available to the public. The underlying database is the same, but the formatting may be preferable to your individual taste between BNSF (exportable results) and UP (easier to scroll).

An interesting example of an FYM yard shared between NS and CSX is Decatur, AL, which demonstrates the complexity of reciprocal switch statuses between just two Class I railroads in one location.

CSX provides a useful glossary of SCRS terminology. Railinc Corp provides a 20-page more detailed set of definitions and rules as well.

Canadian Interswitching

In Canada, the concept of interswitching is a legal requirement similar to reciprocal switching in the US, applying mainly to CN and CP. By law, all customers within 30km of an interchange have the right to route their cars via whichever railroad they choose. In the prairie provinces of AB, SK, and MB, this distance was increased to 160km in 2014, in an effort to encourage competition for grain traffic originating in these areas. However, it is worth noting that few industries far from an interchange take advantage of this limit, with the threat of the competing railroad being given the traffic sufficient to keep rates low and service quality high.

Finding interchange routings

The TSARs can often give hints or instructions on interchange routings - at the very least, they indicate where interchange occurs.

Online tools or guides for interchange routings are available for several railroads:

  • BNSF allows interchange routings to be queried for CN, CSXT, and CP.
  • CSX's Junction Look-Up shows preferred interchange routings to BNSF, CN, KCS, and UP.
  • UP's Interline Routing Agreements show routings for interchange with CP, CSXT, and NS, along with the Mexican railroads, FXE and KCS de Mexico.
  • For Canada, both CN and CP publish full lists of interswitching locations - i.e. all locations at which an interchange can occur, as desired by the customer.

Many players are knowledgeable in common (plus some rather unusual) interchange routings, and chat or the forum are good places to ask if you have queries.

Game logic

In V5.11, FYM's internal logic for generating car destinations was significantly revised to better represent real world car routing, particularly the variety of different routing behaviours that exist.

Loaded car destinations

When loaded, cars will choose a destination at random, unless they are assigned to Car Routing#Dedicated Service, in which case they will be destined for their previous unload destination. Destinations in FYM are assigned realistic traffic levels, and so busier locations such as steel mills will receive more cars. Additionally, cars will avoid cross-loading where possible.

Depending on the car type, FYM will sometimes send multiple cars to the same destination as a larger shipment. Some car types also have restrictions on the distance they can travel when loaded - in particular, woodchips and garbage are highly localised traffic.

Intermodal cars will prefer destinations on the railroad that is loading them, as "steel-wheel" (rail) interchange is relatively uncommon in comparison to "rubber-wheel" interchange, where a container is unloaded at one railroad's terminal and trucked to another railroad's terminal.

Passenger cars will automatically return to their previous origin, as most passenger moves are cyclical in this way.

Empty car destinations

The behaviour of a car when unloaded is highly variable with car type, representing real-world behaviour. These are detailed below. As with loaded cars, some types of cars (e.g. woodchip and garbage cars) have maximum travel distances configured.

In all cases, if a car has a pool assignment, it will return to its pool origin for re-loading.


Cars such as boxcars, gondolas, and flat cars are generally "free-roaming", with the majority owned by railroads, by the TTX car pooling company, or by leasing companies that hire them out freely. Such cars will generally be sent for reloading at a nearby location, to maximise the number of loaded miles (a key objective of the TTX company). Railroad-owned cars that are unloaded on another railroad will be sent to their origin railroad if they are not to be reloaded nearby (this behaviour is not yet enabled on all cars, due to FYM having an imperfect distribution of reporting marks).

Prefer origin area

Cars carrying certain commodities that travel mainly in one direction, such paper, coal, fertilizers, and grain, will generally be routed back to their origin area. In FYM, cars with this routing type have a probability to return to the previous loading location, and otherwise prefer loading locations close to their previous origin. Cars will respect railroad reporting marks - Western railroads are protective of grain cars at harvest time, while Eastern railroads want to ensure a steady supply of high-quality boxcars to paper customers.

Prefer origin

Tank cars and some other types of cars dominated by private owners will prefer to return cars to their previous origin. In particular, tank cars very strongly prefer to return to origin - so much so that real-world car routing rules guarantee that this must occur unless the owner gives other instructions - due to the expense of cleaning a tank car between loads of different commodities.

Intermodal and Autoracks

When unloaded, these cars will become unassigned. Intermodal cars are usually reloaded immediately (with some exceptions on highly directional traffic flows - TSARs will identify movements of empty intermodal cars), while the routing of autoracks is complex, generally aiming to reload them nearby, but with general flows towards Mexico and the Midwest, and is left to players to manage.


A car's journey from origin to destination can be broken into several phases. First, there is a "switch" movement, where the car is collected from a customer. The car may then be interchanged, and then travels some distance in a long-distance "line haul" movement. Several railroads can participate in the line haul segment, with interchanges between each, before the car is finally delivered to its destination in another "switch" movement.

"Line haul" movements are profitable - railroads charge thousands of dollars for such moves, but they require relatively few employees to carry out. In contrast, a "switch" movement is worth only a few hundred dollars, but requires a large number of employees in yards, operating short local trains that move slowly, and interacting with the customer. For a customer, it is also often cheaper and faster to utilise a single railroad for a car movement.

For car routing, this comes into effect when considering the origin and destination of a car. If a car loaded at an origin served by UP, and is destined for a location served by UP and BNSF, FYM will route the car via UP. Alternatively, if the origin is served by multiple railroads and the car is destined for a location served by only one of those railroads, the car will leave the origin with the railroad serving the destination.

This routing logic also considers shortline partners. Railroads will prefer to send cars to associated shortlines, in particular terminal railroads such as the BRC, IHB, or TRRA, which are jointly owned by numerous railroads.

Car pools

Railroads can assign cars to a "pool" (historically called "billed" cars in FYM), which is used mainly to control the movement and assignment of empty cars. FYM represents two kinds of car pooling: shipper pools, and cars in dedicated service.

Shipper Pool

A car assigned to a Shipper Pool will always return to its point of loading after being unloaded. When the car is loaded again, it will choose a destination at random. A car in a shipper pool is indicated by a blue mark in the "P" column of the Train Information Window.

Dedicated Service

A car in Dedicated Service will travel between the same origin and destination points perpetually. This behaviour is intended for use on unit trains, where cars are assigned for use outside of normal car routing rules. A car in a shipper pool is indicated by a yellow mark in the "P" column of the Train Information Window.

Changes from V5.10 and earlier

The "pool" behaviour was previously known as "bill", and acted similarly to Dedicated Service. However, this is not standard behaviour for rail cars in North America, and so when when a car from V5.10 is loaded in V5.11, a "Bill" designation is converted to a Shipper Pool designation by default.

If a group of 30+ "billed" cars of the same type, origin, and destination are found in a train, they are instead considered to be (part of) a unit train and converted to Dedicated Service. Alternatively, if a train consists of 40 or more un-"billed" cars matching those criteria, the cars are assigned to Dedicated Service under the assumption that they form an un-billed unit train.