Difference between revisions of "GWR Power and Weight Classification"
m (Corrected 80XXX from 2-6-2T to 2-6-4T) |
m (additional info) |
||
Line 1: | Line 1: | ||
[[File:7812_Cab_20130806.jpg|thumb|300px|right|Erlestoke Manor was rated axle load class ‘Blue’ and power class D]] | [[File:7812_Cab_20130806.jpg|thumb|300px|right|Erlestoke Manor was rated axle load class ‘Blue’ and power class D]] | ||
− | + | On 1 July 1905 the GWR introduced a system for denoting the haulage capabilities and weight restrictions applicable to the various classes of their locomotives. From mid-1919 this information began to be displayed on the locomotives themselves, enabling railway staff to make a quick assessment of a locomotive's capabilities without the need to refer to tables of data. The display took the form of a coloured disc bearing a letter. The colour of the disc showed the locomotive's axle weight classification, which determined which routes the locomotive could work on. The letter showed the locomotive's power classification, which was used to determine the maximum load it could haul on each route. The disks were initially placed high on the cab side but were moved to a position just above the cab number plate during the Second World War to make them easier to see during blackout conditions.<ref>Wikipedia</ref> | |
− | GWR locomotives currently resident on the SVR were classed as follows: | + | GWR locomotives currently or formerly resident on the SVR were classed as follows: |
{| class="wikitable" | {| class="wikitable" | ||
! Locomotive !! Type!! GWR Power class !! BR Power class!!GWR Axle load class | ! Locomotive !! Type!! GWR Power class !! BR Power class!!GWR Axle load class | ||
Line 50: | Line 50: | ||
|} | |} | ||
Certain routes could be modified as "dotted", for example "Dotted Blue" meant a route could be worked by "Blue" locomotives but subject to a 25mph speed restriction. Locomotives in the lower "Yellow" and "Uncoloured" classes could work the route without this additional speed restriction. | Certain routes could be modified as "dotted", for example "Dotted Blue" meant a route could be worked by "Blue" locomotives but subject to a 25mph speed restriction. Locomotives in the lower "Yellow" and "Uncoloured" classes could work the route without this additional speed restriction. | ||
− | |||
− | |||
===Severn Valley Railway Route Classification=== | ===Severn Valley Railway Route Classification=== | ||
Line 108: | Line 106: | ||
However in BR's Western Region, the old GWR system continued in use until after the Severn Valley Branch closed in 1963, with BR locomotive classes being allocated the relevant GWR route colours. For example a BR Standard Class 4 tank engine such as [[80079]] was given the general BR classification of axle load class RA5 and power class 4MT. Within BR(W) the route availability became "''Class 4 (2-6-4T) (80XXX): Prohibited on 'Yellow' and 'Uncoloured' routes. Restrictions – as for 'Blue' engines.''"<ref>[http://www.michaelclemensrailways.co.uk/?atk=559 ''British Railways Western Region, Locomotive Route Availability, June 1963'' via Michael Clemens]</ref>. | However in BR's Western Region, the old GWR system continued in use until after the Severn Valley Branch closed in 1963, with BR locomotive classes being allocated the relevant GWR route colours. For example a BR Standard Class 4 tank engine such as [[80079]] was given the general BR classification of axle load class RA5 and power class 4MT. Within BR(W) the route availability became "''Class 4 (2-6-4T) (80XXX): Prohibited on 'Yellow' and 'Uncoloured' routes. Restrictions – as for 'Blue' engines.''"<ref>[http://www.michaelclemensrailways.co.uk/?atk=559 ''British Railways Western Region, Locomotive Route Availability, June 1963'' via Michael Clemens]</ref>. | ||
+ | |||
+ | One result of BR's new method of assessing weight restrictions without solely relying on axle weight was that the 5700 class pannier tanks were reclassified from "Blue" to "Yellow" by BR(W) in 1950. The reason given was the low 'hammer blow' that the class produced, which reduced the wear on the track. | ||
==Preservation== | ==Preservation== |
Revision as of 14:46, 4 September 2021
On 1 July 1905 the GWRGreat Western Railway introduced a system for denoting the haulage capabilities and weight restrictions applicable to the various classes of their locomotives. From mid-1919 this information began to be displayed on the locomotives themselves, enabling railway staff to make a quick assessment of a locomotive's capabilities without the need to refer to tables of data. The display took the form of a coloured disc bearing a letter. The colour of the disc showed the locomotive's axle weight classification, which determined which routes the locomotive could work on. The letter showed the locomotive's power classification, which was used to determine the maximum load it could haul on each route. The disks were initially placed high on the cab side but were moved to a position just above the cab number plate during the Second World War to make them easier to see during blackout conditions.[1]
GWRGreat Western Railway locomotives currently or formerly resident on the SVRSevern Valley Railway were classed as follows:
Locomotive | Type | GWRGreat Western Railway Power class | BRBritish Rail or British Railways Power class | GWRGreat Western Railway Axle load class |
---|---|---|---|---|
813 | Ex-PTRPort Talbot Railway & Docks Company | Unclassified | n/a | Unclassified |
1501 | 1500 class | C | 4FThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Red |
2857 | 2800 class | E | 8FThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
4150 | 5101 class large prairie | D | 4MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
4566 | 4500 class small prairie | C | 4MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Yellow |
4930 | 4900 Hall class | D | 5MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Red |
5164 | 5101 class large prairie | D | 4MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
5764 | 5700 class | C | 4FThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. by BRBritish Rail or British Railways(W) | Blue (Yellow from 1950) |
6960 | 6959 Modified Hall class | D | 5MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Red |
7325 | 4300 class | D | 4MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
7714 | 5700 class | C | 4FThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. by BRBritish Rail or British Railways(W) | Blue (Yellow from 1950) |
7802 | 7800 Manor class | D | 5MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
7812 | 7800 Manor class | D | 5MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
7819 | 7800 Manor class | D | 5MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic. | Blue |
GWRGreat Western Railway route classification colours
Routes on the GWRGreat Western Railway were normally classified as "Red", "Blue", "Yellow" or "Uncoloured", according to the maximum axle load permitted by the Civil Engineer, as follows:
Colour | Maximum axle load |
---|---|
Red | 20 Tons |
Blue | 17 tons 12 cwt |
Yellow | 16 tons |
Uncoloured | 14 tons |
Certain routes could be modified as "dotted", for example "Dotted Blue" meant a route could be worked by "Blue" locomotives but subject to a 25mph speed restriction. Locomotives in the lower "Yellow" and "Uncoloured" classes could work the route without this additional speed restriction.
Severn Valley Railway Route Classification
During the Second World War, in order to meet wartime requirements, the line was raised from a yellow to a blue route (although restricted to engines with a maximum axle loading of 17½ tons), before eventually becoming a dotted blue route.[2][note 1] The post-War classification and rules for working the Severn Valley Railway were set out in Section 15 of the 1948 Working Timetable as follows:
- Dotted "Red" route – Hartlebury and Bewdley
- Engines in the “Red” group (with the exception of the ‘King’ and the 2-8-0 47xx Class) may work between Hartlebury and Bewdley, subject to the maximum speed not exceeding twenty miles per hour at any point, also to strict adherence to the following prohibitions and restrictions.
- "Dotted "Blue" route – Bewdley and Iron Bridge and Broseley
- Engines in the “Blue” group (with the exception of the 2-8-0 types) may work between Bewdley and Iron Bridge and Broseley, inclusive, at a maximum overall speed not exceeding 25 miles per hour at any point, subject to the following prohibitions and restrictions.
- "Blue" Route – Buildwas and Shrewsbury
- Engines in the “Red” group (with the exception of the ‘King’ and the 2-8-0 47xx Class) may work over the running lines only between Buildwas and Shrewsbury, provided the speed does not exceed 20 miles per hour at any point and subject to service restrictions.
John Marshall’s history of the Severn Valley Railway also states that special rules applied to 51xx and 81xx ‘large prairies’, which were subject to a 25mph restriction between Victoria Bridge and Linley.[3]
The maximum permitted line speed between Hartlebury and Shrewsbury was 50mph. The additional prohibitions and restrictions referred to mainly related to sidings and weighbridges, although there were details restrictions on the working of locomotives over Victoria Bridge.
Kidderminster to Woofferton Route Classification
Information on the Kidderminster to Bewdley Loop line and the Tenbury Branch was included in Section 12 of the 1948 Working Timetable, as follows:
- Kidderminster and Bewdley
- Any engine in the “Red” group (excluding the ‘King’ class and the 2-8-0, 47xx Class) may work between Kidderminster and Bewdley subject to the maximum overall speed not exceeding 20 miles per hour.
- Bewdley and Woofferton. (Dotted Blue)
- Engines in the “Yellow” group may work between Bewdley and Woofferton subject to service and special speed restrictions.
- Engines in the “Blue” group are authorised to work between Bewdley and Woofferton at a maximum speed of 25 miles per hour subject to the following prohibitions and service speed restrictions.
As with the Severn Valley Branch, the overall line speed was limited to 50 mph, while the prohibitions and restrictions mainly related to sidings and weighbridges.
GWRGreat Western Railway locomotive power classification
The GWRGreat Western Railway allocated locomotives into power classes ranging from Ungrouped (lowest), A to E (highest), and Special (King class) as follows:
Power class | Tractive effort (lb) |
---|---|
Special | Over 38,000 |
E | 33,001 – 38,000 |
D | 25,001 – 33,000 |
C | 20,501 – 25,000 |
B | 18,501 – 20,500 |
A | 16,500 – 18,500 |
Ungrouped | Below 16,500 |
For each route, the working timetable included a table of locomotive classes and the maximum permitted load. For example the 1948 working timetable specified that a ‘small prairie’ such as 4566 was limited to a load of 310 tons between Hartlebury and Shrewsbury, although a load of 335 tons was permitted for “trains liberally timed”. The power classes and loads did not differentiate between Passenger, Freight and Mixed traffic working.
After nationalisation
During the Second World War the LNERLondon & North Eastern Railway developed a somewhat more sophisticated version of the GWRGreat Western Railway's classification system which was adopted by BRBritish Rail or British Railways after nationalisation. Route Availability was based on classes RA 1 to RA 10 and took into account the weight per foot length of a locomotive rather than just the simple axle loading used by the GWRGreat Western Railway, while locomotive power was based on classes 0 to 9 with distinctions made for Passenger, Freight and Mixed Traffic.[4][5]
However in BRBritish Rail or British Railways's Western Region, the old GWRGreat Western Railway system continued in use until after the Severn Valley Branch closed in 1963, with BRBritish Rail or British Railways locomotive classes being allocated the relevant GWRGreat Western Railway route colours. For example a BRBritish Rail or British Railways Standard Class 4 tank engine such as 80079 was given the general BRBritish Rail or British Railways classification of axle load class RA5 and power class 4MTThe British Railways system of classifying steam locomotives by power using a number from 0, least powerful, to 9, most powerful, followed by either F for freight, P for Passenger or MT for Mixed Traffic.. Within BRBritish Rail or British Railways(W) the route availability became "Class 4 (2-6-4T) (80XXX): Prohibited on 'Yellow' and 'Uncoloured' routes. Restrictions – as for 'Blue' engines."[6].
One result of BRBritish Rail or British Railways's new method of assessing weight restrictions without solely relying on axle weight was that the 5700 class pannier tanks were reclassified from "Blue" to "Yellow" by BRBritish Rail or British Railways(W) in 1950. The reason given was the low 'hammer blow' that the class produced, which reduced the wear on the track.
Preservation
When the SVRSevern Valley Railway began operations in 1970, the line was still subject to the 17 tons 12 cwt axle weight restriction. This meant that large locomotives such as 61994 The Great Marquess could not be used until a program of upgrading the line had been undertaken. The successful completion of this means that the SVRSevern Valley Railway has since hosted a GWRGreat Western Railway 'King' class locomotive, as well as similar classes of locomotives from other companies. However Victoria Bridge remains subject to operating procedures which restrict the double-heading of locomotives.
The Light Railway Order under which the SVRSevern Valley Railway operates specifies a maximum speed of 25mph for normal services. Operation up to 50mph may be carried out between Kidderminster and Bewdley when the railway is closed to the public; a recent example being the testing of Metropolitan Railway 0-4-4T No 1 in 2012 prior to its participating in the London Underground events in 2013.
Notes
- ↑ Marshall refers to the line as 'dotted blue' without stating that it was a 'yellow' route pre-War, however the absence of evidence of blue rated locomotives prior to that time suggests this was the case.
See also
- Steam Locomotives
- Locomotives used on the Severn Valley Branch in commercial service
- Great Western Railway
References
- ↑ Wikipedia
- ↑ Smith (1968) pp. 24-25.
- ↑ Marshall (1989) p. 137.
- ↑ devboats.co.uk
- ↑ Wikipedia
- ↑ British Railways Western Region, Locomotive Route Availability, June 1963 via Michael Clemens
Links
GWR Power and Weight Classifiation on Wikipedia
Route availability on Wikipedia
1948 BR(W) Working Timetables on Michael Clemens' website (Section 15 includes the Severn Valley Branch, Section 12 includes Kidderminster to Woofferton)