Low entry bus
As a low-entry bus ( engl. [ Ləʊ 'entrɪ ], low input ) also LE bus or Tiefeinstiegsbus is, in the low-floor technology refers to a concept in which a bus via variable entries and a partial low-floor area in the interior, usually between the front and center door, but the rear area of the passenger compartment is high-floor and can only be reached via steps in the center aisle.
The idea is that not all passengers are dependent on barrier-free vehicles, but only a very small proportion of people with restricted mobility who can be offered low-floor areas in otherwise high-floor vehicles. All others can easily use high-floor car parts and stairs. An LE bus therefore represents a good compromise between the requirements for accessibility, which is increasingly required in local transport tenders, and the advantages of simpler production. According to the EU guidelines, an LE bus is considered a low-floor vehicle and can accordingly meet the tenders for transport services in which low-floor vehicles are required.
The advantages of this design are lower costs; LE buses are around ten percent cheaper to produce and purchase than low-floor buses of the same type with a continuously stepless central aisle, as drive parts from high-floor or truck series production can be used and no expensive special designs such as portal axles for low-floor vehicles are required. Furthermore, the vehicles are more maintenance-friendly because the drive components have more space in the engine compartment, while the underfloor engine and ancillary units in the low-floor bus have to be arranged in a more complicated manner due to the lack of space and are therefore less accessible for maintenance. In low-floor buses, many components are often housed elsewhere in the vehicle due to a lack of space in the engine compartment, such as in boxes under the passenger seats or in roof ducts, and are therefore less accessible for maintenance work. The one-sided loading of tires and brakes is also eliminated with the LE-Bus, since the engine is mostly in the center of the rear; the engine position thus also has a more favorable effect on driving behavior. A conventional engine from truck / industrial production can also be used, which does not require an oil pan lying against the block for installation on a horizontal level, and the larger space in the engine compartment also reduces the accumulated heat. In the rear, high-floor section, more seats can be accommodated, since all the seats can be mounted facing the direction of travel due to the lack of wheel arches there, which enables an increased seating density.
The disadvantage that not all seats are low-floor in the LE bus is put into perspective, since in a low-floor bus the rear seats and the seats on the axles are sometimes also arranged on very high platforms and steps must also be overcome here. These are the places close to the door, especially for passengers with reduced mobility. Furthermore, in a full low-floor bus with an underfloor engine position, the center aisle in the rear is sharply angled and the footwell is interrupted by inconvenient steps and platform attachments. The central aisle in the rear is also relatively narrow. Older low-floor articulated buses or solo vehicles with a third door have steps so that the low-floor bus is not completely barrier-free . On the contrary: the footwell of an LE bus has a smoother surface in the rear because no units have to be built over with boxes protruding into the footwell. Therefore, in addition to the LE buses, full low-floor buses with laterally arranged tower motors are increasingly gaining acceptance , which have a continuously level car floor and so no high - possibly risky - step constructions in the passenger compartment are required.
A possible disadvantage of the LE bus is that it has to be built quite high so that there is sufficient headroom in the high-floor area. The LE models from Mercedes-Benz or Van Hool have a raised vehicle roof in the rear, which also ensures sufficient headroom there. MAN and Solaris , for example, have waived this, even if the LE model of the Lion's City is higher than the low-floor version (recognizable by the significantly higher, black-clad wiper bracket in the windshield). As a result, this bus lacks the necessary headroom in the rear seats due to the roof channels running there and the destination sign box on the last bench.
It was not until the economic constraints of the mostly public transport companies (or public transport authorities ) that LE buses have recently been able to establish themselves on the market as standard vehicles in this country, as the "large" bus manufacturer EvoBus (with the brands Mercedes-Benz , Setra ) and MAN added corresponding vehicles such as the Citaro LE or the Lions City T / TÜ (today LE) to their range.
As early as 1976 , the bus manufacturer Auwärter-Neoplan presented the N 814, a modern low-floor bus with stepless entry, but two steps in front of the rear axle. Only a few examples of this type of vehicle existed, however, and the breakthrough in low-floor technology would not take place until a good 20 years later. The Kässbohrer Fahrzeugwerke established in 1991 with the S 215 NR a series Überlandniederflurbus before that had a conventional, high-floor rear area and thus can be referred to as LE bus. In Sweden , this low-entry concept in the 1990s set already about halfway through. In addition to the Scania CN 113 CLL MaxCi presented in 1992, Volvo also offered corresponding buses with bodies from Säffle or Carrus.
For the German market, the Swedish commercial vehicle manufacturer Scania offered a bus chassis for city buses under the name "FlexCi" in 1994; the body was built by Neoplan (N 4015), which also corresponded to the LE concept with a high-floor section in the rear. While the Setra S 215 NR - albeit in moderate numbers - was ordered by the regional bus companies of the railway and some private companies, the N 4015 on the Scania chassis remained a marginal phenomenon in German-speaking countries.
Some manufacturers also supply articulated buses in an LE version. For example, Solaris Bus & Coach offers the Urbino 18 with CNG drive in an LE variant.
In the case of trolleybuses , on the other hand, low-entry designs are largely unknown, since the entire electrical equipment can be placed relatively freely in the vehicle in a more space-saving manner than mechanical power transmission and independently of the necessary mechanical transmission paths such as cardan shaft guides. The Czech type SOR TN 12 , which in turn is based on the low-entry diesel bus SOR BN 12, and the Solingen TS 1 are among the few exceptions to such an LE trolleybus .
useful information
The term "low entry" is certainly also an Anglicist fashion term of the last few years, although the principle of low entry in the literal sense is not new. Double-decker buses in self-supporting construction have always been low-entry buses in a certain way, since the lower deck does not allow any steps due to the limited vehicle height (in Germany 4.00 meters without special permit), even if under the term "low-entry" barrier-free , d. H. Ground-level access for strollers and wheelchair users is understood, which these buses do not automatically provide.
But there were also developments with passenger-friendly entrances for single-deck buses quite early on. The bus SP 110 (SP for Setra-Pekol) developed jointly by Otto Kässbohrer and Oldenburg bus builder Theodor Pekol in the 1950s had an extremely low floor height of only 50 centimeters with only one step, as this bus, in contrast to the otherwise common mid-engine buses had a horizontal rear engine for the first time. Often the mid-engine buses, despite the fairly high car floor of around 90 centimeters, had a stepless or even stepless rear entrance that could be used as a space for prams. One or two steps led from this standing area to the central aisle to the seats.
This LE concept is used in low-floor technology beyond buses and trams as well, since the drive bogies used to require sufficient space and had to be built over with steps in the interior. This need no longer exists due to the current use of single-wheel chassis or deep-cranked portal bogies. Older high-floor vehicles were often retrofitted with a low-floor center section, so that there is also at least one low-floor entry available for each tram motor vehicle. Municipal or airfield trucks with low cabs such as the Mercedes-Benz Econic are now also referred to as low-entry cabs.
gallery
Neoplan N 814 - first LE bus from 1976
MB Citaro LE MÜ with raised rear
MAN Lion's City T
MAN Lion's City LE (after facelift)
Setra S 215 NO
Volvo B10 BLE with Säffle body
Irisbus Crossway LE
Solaris Urbino LE from the rear
Interior of the Solaris LE, the small distance between the last row of seats and the target sign box is clear
Czech trolleybus type SOR TN 12 in LE version
Individual evidence
- ^ Association of German Transport Companies - Low Floor Technology , accessed on January 14, 2014.
- ^ Auwärter-Neoplan photo archive , accessed on September 15, 2012.
- ↑ Lastauto Omnibus 2/1994
- ↑ Solaris Busmania -New in the low-entry offer , accessed on September 15, 2012.