Variations on a Theme - Realistic rail in North America

[Espee]

OVERVIEW

This topic is a response to the series of ongoing description by ivanfurlanis, describing his approach to realistic railway networking based on prototypical practice in what I call "alpine Europe" - southern Germany, Austria, Switzerland and Northern Italy. Anyone who has NOT seen his posts needs to drop whatever they are doing and check out his screenshots: http://www.tt-forums.net/viewtopic.php?f=47&t=38444 and his topic Realistic Railway Networks http://www.tt-forums.net/viewtopic.php?f=47&t=48355. Mr. Furlanis has inspired quite a few of us fans of mountain railroading, and has motivated me to get off my own posterior and provide some samples of my own OTTD practice for us fans of heavy-duty North American railroading.

Some points to keep in mind:

* The US and Canada are BIG countries, with some rather sparsely settled areas in our western states/provinces. However, those few lines that run through mountains, canyons and deserts move a LOT of tonnage. Two rail lines in the southwestern US, the BNSF's (ex-ATSF) "Transcon" and the UP's (ex-SP) "Sunset Route" move up to 100 trains a day, most of them over 2 km long. CN and CP move some pretty impressive grain trains to ports in British Columbia as well.

* Those mountains come with steep grades and tight curves - grades steeper than 2% (1 in 50) are not uncommon, and UP has TWO locations where mile-long trains loop over themselves to climb mountain ranges in California ALONE. Efforts to provide extra capacity are hampered by real cost and physical limitations - no terraforming trenches across the landscape here!

* Cargo is king in North America - freight trains are the big show here, and in most locations our national passenger rail network does NOT have its own dedicated right-of-way. While the trend of providing excess urban trackage to local commuter rail authorities has resulted in more such system having their own dedicated lines, in many places slow freight, fast freight, commuter AND intercity service must share the same lines - and in a lot of places, this may be bi-directional single track!

I will add some samples of my own practice to keep my OTTD rail networks as prototypical as possible while still playable. Comments and contributions are welcome...

[Espee]

[OTTD] REALISTIC GAME PARAMETERS

A realistic OTTD game requires setting up suitable parameters. I use the following difficulty and advanced settings for the most prototypical North American railroading experience:

DIFFICULTY SETTINGS

• Vehicle Breakdowns: Reduced
  Train Reversing: At end of line, and at stations

ADVANCED SETTINGS

• CONSTRUCTION
  • Allow building on slopes and coasts: On
    Allow building very long bridges: On
  VEHICLES
  • Forbid trains and ships to make 90-degree turns: On
    Vehicles never expire: Off
    Autorenew vehicle when it gets old: Off
    Train acceleration model: Realistic
    Slope steepness for trains: 5%
    Weight multiplier for freight to simulate heavy trains: 3
    Vehicles never expire: Off
  STATIONS
  • Nonuniform stations: On
    Max station spread: 15

[Espee]

SCREENSHOTS - PASSENGER TERMINALS

In days of old before cheap air travel and the Interstate Highways, our larger cities in America had plenty of large stations to rival those of the UK and EU. Common practice pre-1900 was for each railroad company to have their own large terminal near the center of town, along the lines of London or Paris. Later development was the "Union Station" shared by more than one company. In the US, we differentiate between a "station" which has tracks in both directions and through service, and "terminals" where trains enter and leave through one end only. Terminals are often built due to geographic restrictions or existing urban development that makes the necessary condemnation/demolition cost-prohibitive:

Note the example of a six-track passenger terminal here (ignore the two freight tracks for the time being) fed by a simple "ladder" controlled by an entry presignal at the "throat". A reverse-biased crossover (set up to allow serviced trains to return to the station without getting the rest of their orders out of synch) protected by path based signals (PBS) is set up with a minimum of one train length from the station exit signal to the outbound crossover PBS. The EXIT TRACK is the critical choke point, not the entry track, so any maintenance depots are always set up one track length away to keep slow trains from choking up the yard throat. Also note the long platforms - it's easier (and cheaper) to build the longer platforms earlier in the game when possible than have to do the reconfiguring and land acquisition later.

Here we have added a double-track junction and line to the two goods/freight track on the right. A terminal handling a large amount of mail and express ("goods" in OTTD) and even fresh food heading to market would have its own dedicated terminal located on the side of the station with either the easiest topography or the lowest real estate values. Mail and fresh produce in steam days would be handled by slightly older, less capable versions of the typical passenger class locomotives used by the railroad. Later on, high-horsepower Bo-Bo diesel-electrics with appropriate gearing (70 MPH/110 Kph or faster) would haul box cars, reefers (refrigerator cars) or even piggyback trailers before the days of huge dedicated intermodal facilities. With the addition of the freight tracks, we have also incorporated waypoints (referred to as "control points" in current US practice) to direct inbound passenger and goods/express traffic to the appropriate facilities.

The usual practice for a double-track junction would be a grade level (tracks cross each other at grade) "interlocked" facility, which is modeled reasonably well with PBS signals. In this example, however, adding such a junction in the available space would be a problem in that any train waiting for an entry presignal into the terminal would "foul" (block) the junction. In this case, we have adapted the not common BUT prototypically acceptable approach of a "flyunder" or underpass for the main terminal "lead" (entry track). Decision of which track to lower (or elevate) in a multi-level junction is not a trivial matter, and is primarily determined by the following factors in the US:

• COST: not just of building the structure but of acquiring the land.
  TOPOGRAPHY AND ELEVATION: Total change in elevation (rise AND fall) needs to be minimized for effective train handling. You want to avoid a situation where a train climbs a bridge over one track then has to descend to an even lower point a short distance later.
  PASSENGER VS. FREIGHT TRAFFIC: Freight trains in North America are typically long, heavy, and do not have the same power to weight ratio as passenger trains. 2 to 3 HP per ton may be typical for freights, while passenger trains will more likely be rated 8 to 10 HP per ton. Given a choice, a railway civil engineer will keep freight trackage on as level a grade as possible, and construct overpasses (flyovers) and underpasses (flyunders) to divert the passenger traffic accordingly.

I have tended to prefer presignals in earlier games, as they more accurately resemble the type of signaling one would see in an older US terminal. However, the path based signals work perfectly fine, and with the addition of extra "escape tracks" on train can enter the terminal while an other one departs. The PBS signals would most accurately represent a newer "interlocked" station approach as found in post-WWII applications.

[Espee]

SCREENSHOTS - THROUGH STATION EVOLUTION AND DEVELOPMENT

One critical issue facing American railroads was the financial drain of building a large system without a proper traffic base to support it. Many routings of the early transcontinental railroad were influenced not just by geography but the need to tap and develop whatever traffic base was out there to ensure some type of cash flow before the planned route was finished. Not only did branches shoot out to rich mining and agricultural regions, but small towns would offer land for right-of-way to convince the railroad to service their little burg and provide a connection with the big city. Towns that connected with the railhead might bloom into prosperous centers of commerce and trade, or wither into forgotten station stops later. Following are examples of a small "terminal" station on the end of a branch line that evolves into a stop on a high-density trunk line as the years go by:

Schenectady is a small town located somewhere in the northeastern US with local passenger and mail service connecting it with the nearby rail center of Albany. Its four-track stub station is adequately served by a presignal arrangement offering equal access to all tracks.

Mr. Vanderbilt, anxious to tap freight and passenger traffic from the boats on the Big Lakes and provide the fastest service to Metropolis City, pushes the line towards Utica. The new Upstate Line will connect with his Water Level line being built east from the shore of the Really Big Lake, and go through Schenectady. Here the station is being modified for future through service, with two dedicated platforms for each direction. The crossover on the east side of the station has been removed to conform with the new plan, so new crossovers and a maintenance facility have been added to the west site. Local trains from Albany will now arrive on the westbound tracks, discharge mail & pax, move to the maintenance facility for service, and return to the station to load on the eastbound tracks.

The first phase of the line expansion is finished. Local trains still turn around at Schenectady, but through trains can now proceed to Utica, Syracuse, Rochester, and points west.

[Espee]

SCREENSHOTS - THROUGH STATION EVOLUTION (continued)

Mr. Vanderbilt's Open TTD game is going so smashingly well that he can't manage everything himself. He puts his game online to play against Mr. Hill and Mr. Harriman, then provides his game password to Mr. Young and Mr. Perlman, who have been put in charge of all the local passenger and freight services, while Mr. Vanderbilt takes care of all the express trains and his new hush-hush project: the 21st Century Maglev. Mr. Young takes charge of the eastern half of the system and calls his part the Hudson Division. Mr. Perlman's western portion is known as the Mohawk Division. Both agree that the dividing line will be at Schenectady, so Mr. Perlman clones the crossover & maintenance shed arrangement on the east end of the station platform so HIS local trains from Utica can turn around as well.

Mr. Vanderbilt's Maglev project isn't going to well, as nobody has invented the GRF yet in the 1950's. He then tries the next best thing, sets up a couple jet engines on top of an RDC, and by hacking a few parameters and compiling his own build, comes up with a railborne sled that will definitely NOT be found in the main trunk for some time to come. His noteworthy stunt encourages a couple of adventurous local boys to strap JATO bottles on the back of their Ford pickup, and the Darwin Awards were born. Vanderbilt finally discovers NARS 2.03, and decides that four-unit sets of E7s with 52:25 gearing, hauling jade green and silver coaches will do the trick for the time being. His Not Ready for the 21st Century Limited is a big hit, but the local stations are creating havoc with the schedule. Given that his new crack limited bypasses small town stations anyway, he instructs his assistants to build cutoff lines to bypass station congestion points such as Schenectady. Through trains are held at Schenectady to allow the Limited to pass and remain on schedule.

[Espee]

SCREENSHOTS - DOUBLE-TRACK JUNCTIONS

Nothing earth-shattering here, but some relevant points when considering North American practice:

OTTD-Junctions-Ex1.jpg (134.3 KiB) Viewed 4608 times

To claim this is merely the "preferred method" is an understatement. Grade level junctions are pretty much the default standards when dealing with long, heavy American freights. Other methods will ONLY be used when local traffic or topography issues present no other choice! Fortunately, the PBS setup represents a typical American "interlocking" facility pretty well, so game behavior here is pretty realistic. Note the use of waypoints ("control points" in current US practice) to route trains accordingly.

OTTD-Junctions-Ex2.jpg (137.78 KiB) Viewed 4608 times

This is what used to be referred to as a "burrowing junction" on the east coast and is now typically referred to as an "underpass". The tunnel is really "cut and cover": get a bunch of scrapers and 'blades, gouge out a trench, put in concrete retaining walls, and cover the top, and you have "instant tunnel". Preferable where soils are easy to excavate, and there are no problem with the local water table or underground utilities.

OTTD-Junctions-Ex3.jpg (137.46 KiB) Viewed 4608 times

The LAST and usually most EXPENSIVE option is the "flying junction" or "overpass". This approach is almost NEVER used for mainline freight operations, but is quite common for what we call "light rail", which is typically an updated tram/streetcar approach built to almost mainline specs in terms of catenary and track structure (but far more aggressive curves and grades). Think of German strassebahnen running on S-bahn type trackage, and you will get the general idea...

[Espee]

OTTD-Junctions-Ex4.jpg (192.27 KiB) Viewed 4605 times

Of course, for every rule there IS an exception... There are some places where changes in topography make perfect sense for use of a bridge or overpass in a double-track junction. Note the other pointers relevant to all double-tracked junctions...

[bwong]

now where's that like button?

[kamnet]

Great examples, thank you for posting! I tend to limit how much track I use myself since I mainly play just for looks and not for profit, so I just can't imagine laying more than two or three rail lines down in any given area since this isn't realistic in North America at all. I also appreciate the examples of junctions and signaling. I just started using PBS had hadn't quite gotten the hang of them, but with your examples I see what I'm doing wrong.

[L0co_motion]

Looks great!

[bwong]

in your stations they seem very basic, and unsuited for the situation (aesthetics)... Is it just there as an example, or would you recommend different station design?

[Coxx]

Very nice, I allways wanted to know what makes a track layout looking "american".

But here we can see the limits of realism in (O)TTD. X-es should best be avoided here. I usually use fly-overs for two reasons: bridges take less space (until the would be the enhanced tunnel feat in Ottd) and a stoped train will gather speed faster after waiting at the signal.

My favourite RL overpass:
http://www.rbd-erfurt.de/Strecken1/Hall ... n57-2a.jpg

Looking forward to some american station designs.

[Kogut]

What about using buffers?

[GoldRush]

What about other types of junctions? That one you suggested can't be used all of the time.

[Espee]

What about other types of junctions? That one you suggested can't be used all of the time.

I never said that only one type was used. I merely mentioned that certain types were the most prototypical in North America. Keep in mind that freight trains that are 1-2 km long and between 5,000 and 10,000 tons are not uncommon here in the States, and that while grades are unavoidable, you do NOT want excessive "up-and-down" topography that will play havoc with your slack. Having to clean up spilled cars (wagons) on the ground because you derailed the thing ties up traffic a LOT more than merely blocking a grade level crossing for a few extra minutes. Therefore, grade-level type junctions are most prevalent here.