Standardized Roadtype Scheme

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This scheme was originally conceived in order to decrease the amount of neccesary hidden road and tramtrack types. This is done by standardising which labels vehicles and infrastructure should use. The standard also allows for more gameplay depth by having the option to limit vehicles to certain types of roads. It does similarly to the railtype scheme allow mixing of any vehicle set with any infrastructure set. It does however not allow multible infrastructure sets to be used at the same time. It does not prevent it but all of the sets used have to be made to be used with each other, or use diffrent surfaces/types which don't conflict with each other. The standard sets no limit on how vehicle sets can be used.

It is ultimately up to the infrastructure set to chose what roadtypes are avaliable and thereby what vehicles are avaliable. Infrastructure and vehicles can both be in the same set, it is however recommended to be able to dissable the infrastructure with parameters in case the player wants to use a different set for their infrastucture.

Surface / Type [X***]

Describes the road surface / rail type and thus the vehicle type.

Roadtype:

Letter Meaning (Road) Powered Roadtypes Recomended vehicle set fallbacks
R Regular Road RI(S)
P Passenger-only RPI(S) R
G Guided busway RPG P then R
I Industrial Site (ISR) I R
B Bicycle Lane RB(Z) R
W Waterway W
A Amphibious on road (hidden) RPI(S)W R
S Snowy or Iced Track S
a Amphibious on snow (hidden) SW S
Z Pedestrian Zone Z
E Eyecandy E
p Pump/Pipeline p

Tramtype:

Letter Meaning (Tram) Powered Tramtypes Recomended vehicle set fallbacks
R Regular Rail RI(M)
P Passenger-only RPI(M) R
I Industrial Site (ISR) I R
B Bicycle Lane (R)B
S Suspended Monorail S
M Metro M(RP)
O Trackless trams O
E Eyecandy/Electrical infrastructure E

It is the vehicle set's responsibility to implement fallbacks to other appropriate surfaces. It is also up to the author to decide if they want to do it or not. This means that road/tramtrack sets shouldn't add these to their alternative_roadtype_list (NML) and alternative_tramtype_list (NML)

It is up to the track set to implement all powered roadtypes in the powered_roadtype_list (NML). The same goes for tramtypes: powered_tramtype_list (NML). It is further advised to implement support for the roadtypes/tramtypes in brackets, if applicable.

Hidden roadtypes for compatibility should be implemented by road sets. It is up to the author to decide if they want to implement it as a hidden roadtype or not.

Speed / Feature [*X**]

Any character may be used for roads, but at least one road must have "A".

Vehicles should use "A".

Terrain / Stability [**X*]

Describes the roughness of the road surface / trackbed stability, and thus the vehicle tier.

Letter Meaning Powered Roadtypes
a Very slow / rough / light aA
A Slow / rough / light aAB
B Regular ABC
C Fast / stable BCc
c Very fast / stable Cc

If all classes aren't defined by the road set, the other ones should be in the alternative_roadtype_list (NML). The same goes for tramtypes: alternative_tramtype_list (NML).

Road vehicle sets should not implement fallbacks for terrain / stability.

Classes "a" and "c" are entirely optional for road/tramtype sets and should under no circumstances be used by vehicles.

Energy [***X]

Describes the energy source of the track / vehicle.

Generic classes:

Letter Meaning (Road) Meaning (Tram) Vehicle set fallback
N None None
E Overhead electrified (Catenary) Overhead electrified (Catenary)
G Ground electrified Ground electrified
Z Ground and overhead electrified Ground and overhead electrified E or G

Specialized classes:

Letter Meaning (Road) Meaning (Tram) Vehicle set fallback
3 n/a Third Rail G
4 n/a Fourth Rail 3 then G
C n/a Cable G

A tramtrack set that only uses specialized types, should map the generic types to the most suitable specialized type in the set with the help of the alternative_tramtype_list (NML).

The default labels (ROAD, ELRL) and non-standard labels

OpenTTD will allways define ROAD and ELRL incase there are vehicles for them. It is therefore recomended to have these present in the set so that you can map them to appropriete labels from the standard. There are a few ways of doing this:

Vehicle set authors might want to add the default labels and non-standard labels as a fallback. If not implemented for the defualt labels, their vehicles won't show up on the default roads and/or tracks, leading to countless bug reports from players. Non standard labels that might be worth adding fallbacks too are: ELRD, RAIL, HAUL and probably some more.

Summary for Road/Tramtrack sets

This section summarizes the above for road/tramtrack sets.

[X***] Surface / Type
  • Chose which Surfaces and types you want in your set and give them the correct powered_roadtype_list (NML) or powered_tramtype_list (NML).
  • If you only provide roads/tramtracks for one surface/type, consider leaving some free road/tramtypes so a player can load an additional set for some other type.
[*X**] Speed / Feature
  • Make sure class A is always available.
  • Use B, C and so on if you have multible roads/tramtracks with the otherwise the same label.
[**X*] Terrain / Stability
[***X] Energy source type class
Default labels [ROAD, ELRL] and non-standard labels

Summary for vehicle sets

This section summarizes the above for vehicle sets.

[X***] Surface / Type
  • Use the surface / type class that matches the vehicle;
  • Define a fallback type via the road/tramtype table in case you want the vehicle to be available on a different road or tramtrack if no matching road/tramtrack set is loaded.
    • Specialized subtypes like "G" might not always be available. If you want those vehicles to be still available then, fall back the the generic class (e.g. "P" or "R").
[*X**] Speed / Feature
  • Always use class A for every vehicle.
[**X*] Terrain / Stability
  • Use A, B or C depending on where you want your vehicles to be able to drive.
    • A is used for slow offroad capable vehicles which aren't allowed on Motorways and similar Roads
    • B is used for vehicles which can drive offroad but are also allowed on Motorways.
    • C is used for vehicles which can't go offroad or similar.
    • Use B if you aren't sure what to chose.
  • Never use a or c.
[***X] Energy source type class
  • Use the energy source type class that matches the vehicle;
  • When using specialized classes, define a fallback type via the railtype table in case you want the vehicle to be available if no matching track set is loaded.
Default labels [ROAD, ELRL] and non-standard labels
  • Define a fallback type to the default labels via the road/tramtype table in case you want the vehicle to be available on the default roads/track if no matching set is loaded.
  • Do the same for any non-standard labels that may be relevant.


Be as specific as you want when selecting the road/tramtype, it is the job of the road/track set to select a playable, reduced subset out of all possible type combinations.

Example of fallback order for vehicle sets

Unchanged label Fallback order
GACE (road) GACE -> PACE -> RACE -> (ROAD)
PAB4 (tram) PAB4 -> PAB3 -> PABG -> RAB4 -> RAB3 -> RABG
IAAG (road) IAAG -> RAAG
AACE (road) AACE -> RAAE -> (ELRD)
RABE (tram) RABE -> (ELRL)
PAAN (tram) PAAN -> RAAN -> (RAIL)

Forum topic

Feel free to discuss and ask questions about the scheme at the forum topic Here.

Possible additions

To be discussed in the forum topic...

Surface / Type [X***]

Describes the road surface / rail type and thus the vehicle type.

Tramtype:

Letter Meaning (Tram) Powered Tramtypes Recomended vehicle set fallbacks
X or x Multiple guidance systems or guages (Depends on intent; only two tramtype rail system combinations can exist for a given set of standardized labels - i.e. XABE and xABE - making it necessary to plan accordingly)

Energy [***X]

Describes the energy source of the track / vehicle.

Generic classes:

Letter Meaning (Road) Meaning (Tram) Vehicle set fallback
i Eyecandy/Pipeline Infrastructure Eyecandy/Electric & Telecom Infrastructure N/A

Specialized classes:

Letter Meaning (Road) Meaning (Tram) Vehicle set fallback
X N/A Multiple systems of electricity Use with surface X or x (e.g. XABX and xABX) or surface R (rail-based tramtype). For use only when at least one standardized label is an energy supply and multiple non-conflicting energy types are all at the same level, such as electrified, ground electrified and trackless tram overlap
x N/A Multiple systems of guidance, incompatible Use with surface X or x (e.g. XABx and xABx). For use when tramtypes are at different heights but all are fundamentally incompatible (i.e. suspended monorail, tram and pneumatic metro)
0-2 & 5-9 N/A Multiple systems of guidance, mix of compatible/incompatible For use when tramtypes are a mix of compatible and fundamentally incompatible (i.e. electrified, ground electrified, trackless tram, suspended monorail, tram and pneumatic metro); Do not set powered_railtype_list for these, instead use alternative_railtype_list, or define these in another label's powered_railtype_list (i.e. XAB0/XAB1/XAB2/XAB5/.../XAB9 for XABE/XABX and RAB0/RAB1/RAB2/RAB5/.../RAB9 for RABN/RABE/RABX).
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