Difference between revisions of "UIC classification"
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| − | The | + | The arrangement of wheels on steam locomotives and small diesel locomotives is normally described using [[Whyte notation]] which specifies the number of powered and unpowered wheels, for example 0-6-0 or 4-6-2. This system does not work well for the more complicated arrangements found in large diesel locomotives which may have bogies containing both powered and unpowered wheels and/or using single or multiple traction motors. Their wheel arrangement is therefore normally described using the more flexible '''UIC classification system''' which denotes the number of axles (as opposed to wheels) and specifies whether each is powered or unpowered. |
| − | + | The international standard UIC notation includes the following conventions to describe axles: | |
| − | * | + | *An '''upper case letter''' indicates the number of consecutive driving axles, starting at A for a single axle. Thus a single C would indicate three powered axles, connected by driving rods or gears, all mounted in the locomotive's frame (Whyte notation: 0-6-0), while BB would indicate four powered axles all mounted in the locomotive's frame, driven in pairs (Whyte notation: 0-4-4-0). |
| − | + | *The '''lower case suffix o''' when applied to two or more driving axles denotes that they are individually driven by separate traction motors rather than by a shared traction motor or other power source. | |
| − | + | *A '''number''' indicates the number of consecutive non-driving axles. | |
| − | * | ||
| − | |||
| − | * | ||
| − | The | + | The presence of bogies is denoted in one of two ways: |
| + | *Where the bogie only contains one type of axle, a "'''prime sign'''" (a single quotation mark) is added to the relevant letter(s) to denote that they are mounted on a bogie. Thus Co'Co' denotes a pair of bogies, each with three powered axles individually driven by traction motors. | ||
| + | *Where the bogie contains several different axle types, '''Brackets''' are used to group together letters and numbers describing the same bogie or truck. Thus (A1A)(A1A) indicates two three-axle bogies, each with the outer two axles driven by separate traction motors and an unpowered central axle. | ||
| − | Oliver Bulleid, the Chief Mechanical Engineer of the Southern Railway, used a modified version of the UIC method to number certain of his steam locomotives. A West Country/Battle of Britain class locomotive would be numbered in a pattern 21C XXX. The first two numbers referred to the number of axles used for leading and trailing wheels, the third letter referred to the number of axles used for driving wheels using the normal UIC classification substitution A=1, B=2, C=3 etc. XXX was the unique identification of the particular locomotive, hence [[SR 34027 Taw Valley | Taw Valley]] entered service as 21C127. | + | The UK generally uses a modified version of this notation (sometimes referred to as "British classification") where the prime sign (single axle) and brackets (multiple axles per bogie) are replaced by a '''hyphen''' denoting the separation between groups of axles in a manner more akin to Whyte notation. Thus B'B' internationally equates to B-B in the UK, Bo'Bo' equates to Bo-Bo, (A1A)(A1A) equates to A1A-A1A and so on. The SVR Wiki follows the UK structure. |
| + | |||
| + | Examples found in diesels currently on the SVR are as follows: | ||
| + | |||
| + | {| class="wikitable sortable" | ||
| + | !British classsification !! UIC classification !! Description !! Examples | ||
| + | |- | ||
| + | |B || B || 2 powered axles connected by driving rods, no bogies||[[Ruston and Hornsby 165hp Diesel Shunter 319290|319290]], [[D2960]], [[D2961]] | ||
| + | |- | ||
| + | |C ||C || 3 powered axles connected by driving rods, no bogies || BR Class 08, Class 09, Class 14 | ||
| + | |- | ||
| + | |A1A-A1A|| (A1A)(A1A)|| Two bogies or wheel assemblies under the unit. Each bogie has one powered axle, one idle axle, and another powered axle. The powered axles are individually driven by traction motors.|| BR Class 31 | ||
| + | |- | ||
| + | |BB||BB|| Four powered axles all mounted in the locomotive's frame, driven in pairs, i.e. each pair of axles is connected by driving rods or gears.|| [[BR Class 42 D821 Greyhound | BR Class 42]] | ||
| + | |- | ||
| + | |B-B|| B'B'|| Two bogies or wheel assemblies under the unit. Each bogie has two powered axles, connected by driving rods or gears.||[[ BR Class 35 D7029| BR Class 35]] | ||
| + | |- | ||
| + | |Bo-Bo||Bo'Bo'|| Four axles in two individual bogies, all driven by their own traction motors.|| [[BR Class 33 33108|BR Class 33]] | ||
| + | |- | ||
| + | |C-C||C'C'|| Two bogies or wheel assemblies under the unit, each with three powered axles, mechanically connected by driving rods or gears.||BR Class 52 | ||
| + | |- | ||
| + | |Co-Co||Co'Co'|| Two six-wheeled bogies with all axles powered, with a separate motor per axle. || [[BR Class 37 37308|BR Class 37]], BR Class 50 | ||
| + | |- | ||
| + | |1Co-Co1||(1Co)(Co1)|| Two eight-wheeled bogies, with three axles (six wheels) powered by separate motors for each axle, and an additional unpowered axle at the outer end of each bogie to reduce the axle load (the weight resting on each axle).||[[ BR Class 40 40106 Atlantic Conveyor|BR Class 40]] | ||
| + | |} | ||
| + | |||
| + | As noted above, the wheel arrangement on steam locomotives and small diesel locomotives is generally described using [[Whyte notation]], although it can of course also be described in the UIC classification system. Oliver Bulleid, the Chief Mechanical Engineer of the Southern Railway, used a modified version of the UIC method to number certain of his steam locomotives. A West Country/Battle of Britain class locomotive would be numbered in a pattern 21C XXX. The first two numbers referred to the number of 'unpowered' axles used for leading and trailing wheels, the third letter referred to the number of 'powered' axles used for driving wheels using the normal UIC classification substitution A=1, B=2, C=3 etc. XXX was the unique identification of the particular locomotive, hence [[SR 34027 Taw Valley | Taw Valley]] entered service as 21C127. | ||
==See also== | ==See also== | ||
[[Diesel Locomotives]] | [[Diesel Locomotives]] | ||
| + | |||
| + | ==References== | ||
| + | |||
| + | ==Links== | ||
| + | *[https://en.wikipedia.org/wiki/UIC_classification_of_locomotive_axle_arrangements UIC classification of locomotive axle arrangements] (Wikipedia) | ||
Revision as of 14:58, 2 August 2021
The arrangement of wheels on steam locomotives and small diesel locomotives is normally described using Whyte notation which specifies the number of powered and unpowered wheels, for example 0-6-0 or 4-6-2. This system does not work well for the more complicated arrangements found in large diesel locomotives which may have bogies containing both powered and unpowered wheels and/or using single or multiple traction motors. Their wheel arrangement is therefore normally described using the more flexible UICUnion Internationale des Chemins de fer (International Union of Railways) classification system which denotes the number of axles (as opposed to wheels) and specifies whether each is powered or unpowered.
The international standard UICUnion Internationale des Chemins de fer (International Union of Railways) notation includes the following conventions to describe axles:
- An upper case letter indicates the number of consecutive driving axles, starting at A for a single axle. Thus a single C would indicate three powered axles, connected by driving rods or gears, all mounted in the locomotive's frame (Whyte notation: 0-6-0), while BB would indicate four powered axles all mounted in the locomotive's frame, driven in pairs (Whyte notation: 0-4-4-0).
- The lower case suffix o when applied to two or more driving axles denotes that they are individually driven by separate traction motors rather than by a shared traction motor or other power source.
- A number indicates the number of consecutive non-driving axles.
The presence of bogies is denoted in one of two ways:
- Where the bogie only contains one type of axle, a "prime sign" (a single quotation mark) is added to the relevant letter(s) to denote that they are mounted on a bogie. Thus Co'Co' denotes a pair of bogies, each with three powered axles individually driven by traction motors.
- Where the bogie contains several different axle types, Brackets are used to group together letters and numbers describing the same bogie or truck. Thus (A1A)(A1A) indicates two three-axle bogies, each with the outer two axles driven by separate traction motors and an unpowered central axle.
The UK generally uses a modified version of this notation (sometimes referred to as "British classification") where the prime sign (single axle) and brackets (multiple axles per bogie) are replaced by a hyphen denoting the separation between groups of axles in a manner more akin to Whyte notation. Thus B'B' internationally equates to B-B in the UK, Bo'Bo' equates to Bo-Bo, (A1A)(A1A) equates to A1A-A1A and so on. The SVRSevern Valley Railway Wiki follows the UK structure.
Examples found in diesels currently on the SVRSevern Valley Railway are as follows:
| British classsification | UICUnion Internationale des Chemins de fer (International Union of Railways) classification | Description | Examples |
|---|---|---|---|
| B | B | 2 powered axles connected by driving rods, no bogies | 319290, D2960, D2961 |
| C | C | 3 powered axles connected by driving rods, no bogies | BRBritish Rail or British Railways Class 08, Class 09, Class 14 |
| A1A-A1A | (A1A)(A1A) | Two bogies or wheel assemblies under the unit. Each bogie has one powered axle, one idle axle, and another powered axle. The powered axles are individually driven by traction motors. | BRBritish Rail or British Railways Class 31 |
| BB | BB | Four powered axles all mounted in the locomotive's frame, driven in pairs, i.e. each pair of axles is connected by driving rods or gears. | BR Class 42 |
| B-B | B'B' | Two bogies or wheel assemblies under the unit. Each bogie has two powered axles, connected by driving rods or gears. | BR Class 35 |
| Bo-Bo | Bo'Bo' | Four axles in two individual bogies, all driven by their own traction motors. | BR Class 33 |
| C-C | C'C' | Two bogies or wheel assemblies under the unit, each with three powered axles, mechanically connected by driving rods or gears. | BRBritish Rail or British Railways Class 52 |
| Co-Co | Co'Co' | Two six-wheeled bogies with all axles powered, with a separate motor per axle. | BR Class 37, BRBritish Rail or British Railways Class 50 |
| 1Co-Co1 | (1Co)(Co1) | Two eight-wheeled bogies, with three axles (six wheels) powered by separate motors for each axle, and an additional unpowered axle at the outer end of each bogie to reduce the axle load (the weight resting on each axle). | BR Class 40 |
As noted above, the wheel arrangement on steam locomotives and small diesel locomotives is generally described using Whyte notation, although it can of course also be described in the UICUnion Internationale des Chemins de fer (International Union of Railways) classification system. Oliver BulleidOliver Vaughan Snell Bulleid, Chief Mechanical Engineer (CME) of the Southern Railway 1937-1948, the Chief Mechanical Engineer of the Southern Railway, used a modified version of the UICUnion Internationale des Chemins de fer (International Union of Railways) method to number certain of his steam locomotives. A West Country/Battle of Britain class locomotive would be numbered in a pattern 21C XXX. The first two numbers referred to the number of 'unpowered' axles used for leading and trailing wheels, the third letter referred to the number of 'powered' axles used for driving wheels using the normal UICUnion Internationale des Chemins de fer (International Union of Railways) classification substitution A=1, B=2, C=3 etc. XXX was the unique identification of the particular locomotive, hence Taw Valley entered service as 21C127.
