Lowbridge double-deck bus
Encyclopedia
A lowbridge double-deck bus is a double-decker bus
which has an asymmetric interior layout, enabling the overall height of the vehicle to be reduced compared to that of a conventional double-decker bus. The upper deck gangway is offset to one side of the vehicle, normally the offside (or driver's side), and is sunken into the lower deck passenger saloon. Low railway bridges
were the main reason that a reduced height was desired.
. However, the lowbridge type started to become obsolete when low-height chassis were developed, which used a dropped-centre rear axle to enable the lower deck gangway to be lowered. This enabled a low-height vehicle to be built without the need for the cumbersome seating layout upstairs. The first such design was the Bristol Lodekka
which was introduced by Bristol
in 1949. It had a height of around 13 in 6 in (4.11 m) compared to a typical height of around 14 in 6 in (4.42 m) for a conventional highbridge double-decker. It was however only available to nationalised bus companies (Bristol itself being part of the state-owned sector at that time). Other low-height double-deckers included the Dennis Loline
(a version of the Bristol Lodekka built under licence); the AEC Bridgemaster and Renown; and the Albion Lowlander (a low-height version of the Leyland Titan PD3). The rear-engined Daimler Fleetline
and Bristol VR
were also low-height chassis. Nonetheless, despite the advent of the low-height chassis, the last lowbridge double-decker was not built until 1968.
When the rear-engined Leyland Atlantean
was first introduced in 1958, it did not have a dropped-centre rear axle, even though the prototype had featured one. As a result, some Atlanteans were built to a "semi-lowbridge" layout, with the front half of the upper deck laid out conventionally, and a side gangway with raised seating area towards the rear.
A special situation existed in Beverley
, in the East Riding of Yorkshire, where buses had to pass under the arched structure of Beverley Bar. To facilitate this, East Yorkshire Motor Services
had a number of double-deckers built with special roofs of severely arched profile to match the shape of the bridge.
A notable lowbridge bus is Barton Transport
's no. 861, registered 861 HAL. It is unique in combining a low-height chassis (Dennis Loline II) with lowbridge bodywork, built by Northern Counties. With the combined effect of both these height reduction techniques, the height of the vehicle is less than 12 in 6 in (3.81 m), which remains the lowest ever for a British closed-top double-decker.
The last lowbridge double-decker to be built was bought by Bedwas and Machen
UDC, a small municipal bus fleet in south Wales, in 1968. It is a Leyland Titan PD3 with bodywork built by Massey of Wigan, and is registered PAX 466F. Following its sale by B&MUDC's successor, Rhymney Valley District Council, it was operated by Stevensons of Uttoxeter, and subsequently by MK Metro
of Milton Keynes.
Double-decker bus
A double-decker bus is a bus that has two storeys or 'decks'. Global usage of this type of bus is more common in outer touring than in its intra-urban transportion role. Double-decker buses are also commonly found in certain parts of Europe, Asia, and former British colonies and protectorates...
which has an asymmetric interior layout, enabling the overall height of the vehicle to be reduced compared to that of a conventional double-decker bus. The upper deck gangway is offset to one side of the vehicle, normally the offside (or driver's side), and is sunken into the lower deck passenger saloon. Low railway bridges
Overpass
An overpass is a bridge, road, railway or similar structure that crosses over another road or railway...
were the main reason that a reduced height was desired.
Origins
The lowbridge design was introduced and patented by Leyland in 1927 on their Titan TD1 chassis. Early examples were delivered to Glasgow Corporation amongst other operators. One of the Glasgow vehicles is preserved at the Scottish Vintage Bus Museum, Lathalmond, Fife.Disadvantages
A major disadvantage of this layout was the inconvenient seating layout, with four-abreast seats upstairs making it difficult for passengers to manoeuvre past each other if those farthest from the gangway needed to alight first. A second disadvantage was the restricted headroom for passengers on the offside of the lower deck, as a result of the encroachment of the upper deck gangway. It was often the case that passengers would bump their heads on it when standing up to alight.Alternatives
At first, there was no viable alternative to the lowbridge design, apart from the use of single-decker busSingle-decker bus
A single-decker bus or single-decker is a bus that has a single deck for passengers. Normally the use of the term single-decker refers to a standard two-axled rigid bus, in direct contrast to the use of the term double-decker bus, which is essentially a single decked bus with an extra deck and...
. However, the lowbridge type started to become obsolete when low-height chassis were developed, which used a dropped-centre rear axle to enable the lower deck gangway to be lowered. This enabled a low-height vehicle to be built without the need for the cumbersome seating layout upstairs. The first such design was the Bristol Lodekka
Bristol Lodekka
The Bristol Lodekka was a low-height double-decker bus built by Bristol Commercial Vehicles in England.Bristol manufactured over 5,200 Lodekkas from 1949 to 1968, as a standard double-deck vehicle for the UK state-owned bus sector. With all examples bodied by Eastern Coach Works in Lowestoft, they...
which was introduced by Bristol
Bristol Commercial Vehicles
Bristol Commercial Vehicles was a vehicle manufacturer of in Bristol, England. Most production was of buses but trucks and railbus chassis were also built....
in 1949. It had a height of around 13 in 6 in (4.11 m) compared to a typical height of around 14 in 6 in (4.42 m) for a conventional highbridge double-decker. It was however only available to nationalised bus companies (Bristol itself being part of the state-owned sector at that time). Other low-height double-deckers included the Dennis Loline
Dennis Loline
The Dennis Loline is a double-decker bus built by Dennis between 1958 and 1967. It is essentially the same as the Bristol Lodekka but has an upgraded Dennis chassis.Aldershot and District Traction was the largest operator of the Dennis Loline....
(a version of the Bristol Lodekka built under licence); the AEC Bridgemaster and Renown; and the Albion Lowlander (a low-height version of the Leyland Titan PD3). The rear-engined Daimler Fleetline
Daimler Fleetline
The Daimler Fleetline is a rear-engined double-decker bus chassis built between 1960 and 1973 in Coventry, Warwickshire, England, and from 1973 until 1980 in Farington, Lancashire, England. However, the last complete vehicle did not enter service until 1983...
and Bristol VR
Bristol VR
The Bristol VR was Bristol's rear-engined bus chassis, designed as a competitor to the Leyland Atlantean and Daimler Fleetline.-Development:...
were also low-height chassis. Nonetheless, despite the advent of the low-height chassis, the last lowbridge double-decker was not built until 1968.
When the rear-engined Leyland Atlantean
Leyland Atlantean
The Leyland Atlantean is a model of double-decker bus built by Leyland in the United Kingdom from 1958 to 1986....
was first introduced in 1958, it did not have a dropped-centre rear axle, even though the prototype had featured one. As a result, some Atlanteans were built to a "semi-lowbridge" layout, with the front half of the upper deck laid out conventionally, and a side gangway with raised seating area towards the rear.
A special situation existed in Beverley
Beverley
Beverley is a market town, civil parish and the county town of the East Riding of Yorkshire, England, located between the River Hull and the Westwood. The town is noted for Beverley Minster and architecturally-significant religious buildings along New Walk and other areas, as well as the Beverley...
, in the East Riding of Yorkshire, where buses had to pass under the arched structure of Beverley Bar. To facilitate this, East Yorkshire Motor Services
East Yorkshire Motor Services
East Yorkshire Motor Services is a large bus and coach operator which operates throughout Kingston upon Hull, the East Riding of Yorkshire, the North Yorkshire coast and the North York Moors. In and around Scarborough, EYMS operates as Scarborough & District Motor Services...
had a number of double-deckers built with special roofs of severely arched profile to match the shape of the bridge.
Notable vehicles
Barton Transport
Barton Transport plc was a British bus and coach operator based in Chilwell, Nottinghamshire. It commenced its first service in 1908. Its fleet and operations were sold to Wellglade in 1989, and the combined operations later became Trent Barton...
's no. 861, registered 861 HAL. It is unique in combining a low-height chassis (Dennis Loline II) with lowbridge bodywork, built by Northern Counties. With the combined effect of both these height reduction techniques, the height of the vehicle is less than 12 in 6 in (3.81 m), which remains the lowest ever for a British closed-top double-decker.
The last lowbridge double-decker to be built was bought by Bedwas and Machen
Bedwas and Machen
Bedwas and Machen was an urban district in the administrative county of Monmouthshire from 1912 to 1974, In 1974 it became a community in the district of Rhymney Valley, Mid Glamorgan....
UDC, a small municipal bus fleet in south Wales, in 1968. It is a Leyland Titan PD3 with bodywork built by Massey of Wigan, and is registered PAX 466F. Following its sale by B&MUDC's successor, Rhymney Valley District Council, it was operated by Stevensons of Uttoxeter, and subsequently by MK Metro
MK Metro
MK Metro was the main bus operator in Milton Keynes in the English county of Buckinghamshire. In February 2006, it was purchased by Arriva Shires & Essex...
of Milton Keynes.
See also
- Bus manufacturingBus manufacturingBus manufacturing is a specific sector of the automotive industry, which carries out the manufacturing of buses and coaches.-History:Bus manufacturing had its earliest origins in carriage building. Other bus manufacturers had their origins in truck manufacturing...
- AEC Regent IIIAEC Regent IIIThe AEC Regent III was a type of double-decker bus chassis manufactured by AEC.It was mainly built for operation outside London and overseas. It could be fitted with AEC's 9.6-litre diesel engine , 'Wilson' preselective epicyclic gearbox The AEC Regent III (also known as Regent 3 or Regent Mark...
- List of buses