Tender for high-capacity buses for SMRT
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What a crowd on TIB1111P and TIB1242U today, on 960
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Originally posted by carbikebus:
I prefer the Cummins Enviro 500 over any other DDs but too bad the previous Cummins Dennis left a skeptical remarks on our PTO.I believe Cummins has improve since it became Alexander-Dennis.
Would be great if SMRT gets Enviro 500, or else Scania K310UD or a MAN 4x2 dd chassis.
Originally posted by vicamour:A lot of these services ply along DTL western wing. When DTL opens, most of these services don't even need to use high capacity buses. Some of the route might even be axed or shortern.
And some of these services are affected by low branches along Dunearn Road. I would suggest LTA and NEA to work together to relocate these low branch trees and replace them with high branching trees, thus to allow double deckers to ply along the road. It is such a waste that double deckers can't ply along that stretch of road just because of low tree branches to provide a better bus service overall.
Worse that because of this, many commercial vehicles as well, especially large mobile cranes and container trucks have to make a big detour just because of this. Wasting fuel and money for companies.
If you look into many of the routes along Dunearn Road, their demands will be dropped once DTL opens.
And just look at Henderson Road, low branches but SBST still manages to use single deckers for all the services there.So other than demand drop in future, these services can just use single deck buses. But I gonna agree that NEA and LTA should do something with the trees along the road. The problem shouldn't stay like this forever.
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Originally posted by SBS 1000U:
Would be great if SMRT gets Enviro 500, or else Scania K310UD or a MAN 4x2 dd chassis.
If you look into many of the routes along Dunearn Road, their demands will be dropped once DTL opens.
And just look at Henderson Road, low branches but SBST still manages to use single deckers for all the services there.So other than demand drop in future, these services can just use single deck buses. But I gonna agree that NEA and LTA should do something with the trees along the road. The problem shouldn't stay like this forever.
SMRT style they dun like their high capacity buses to be less than their normal 12m ones.Look at O405G trend,MK I & II 288hp/1200nm,Volgren and Habit 292hp/1300nm.
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Originally posted by TIB1234T:
I have seen TIB866B on 858 at WRI picking up passengers at the 903/858/969 berth...
I realised that TIB866B did 858 before it was even amended to ply Jalan Kayu in 2001.
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Originally posted by d143b2:
for bendies on 858
two places with problems
CGA Terminal 1,2,3
bus bay cannot handle bendies as it blocks other bus services behind
if the bay is the rear most, still not possible. the only solution is to give 858 a dedicated bay on the other side.
Jln Kayu Ter
this should be skipped for 858
Dedicated bay is good. Separates SBST and SMRT.
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Originally posted by carbikebus:
SMRT style they dun like their high capacity buses to be less than their normal 12m ones.Look at O405G trend,MK I & II 288hp/1200nm,Volgren and Habit 292hp/1300nm.
So we expect to see high capacity bus to have more than 320hp and above 10000cc?
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Originally posted by carbikebus:
SMRT style they dun like their high capacity buses to be less than their normal 12m ones.Look at O405G trend,MK I & II 288hp/1200nm,Volgren and Habit 292hp/1300nm.
I think it is better to get the model providing that kind of power but using engines less than 10 litres. Think of the road tax and fuel comsumption and the related cost. Now fuel not cheap too.
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Originally posted by SBS 1000U:
Would be great if SMRT gets Enviro 500, or else Scania K310UD or a MAN 4x2 dd chassis.
If you look into many of the routes along Dunearn Road, their demands will be dropped once DTL opens.
And just look at Henderson Road, low branches but SBST still manages to use single deckers for all the services there.So other than demand drop in future, these services can just use single deck buses. But I gonna agree that NEA and LTA should do something with the trees along the road. The problem shouldn't stay like this forever.
The deal is that LTA has not found it necessary to shed off the low branches. Most services operating on this stretch are SMRT.
67, 171, 700, 960 that use bendies for clearing high load.
SBS services: 48, 66, 170
The load on 48 does not warrant DDs. 170 cannot use DDs or bendy coz of JB.
LTA is not going to shed off branches only for 66. The service has 65, 64 in parallel from Little India and has 960, 67 in parallel all along Bukit Timah / Dunearn. Then has 157, 174 in parallel. Hence, the heavy loading can be compensated by other buses.
Once SMRT decides to move to DDs, it will give LTA incentive to shed off the branches to accommodate services 66, 67, 700, 960. LTA is just waiting for the right time and need to do it.
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Originally posted by BusAnalayzer:
The deal is that LTA has not found it necessary to shed off the low branches. Most services operating on this stretch are SMRT.
67, 171, 700, 960 that use bendies for clearing high load.
SBS services: 48, 66, 170
The load on 48 does not warrant DDs. 170 cannot use DDs or bendy coz of JB.
LTA is not going to shed off branches only for 66. The service has 65, 64 in parallel from Little India and has 960, 67 in parallel all along Bukit Timah / Dunearn. Then has 157, 174 in parallel. Hence, the heavy loading can be compensated by other buses.
Once SMRT decides to move to DDs, it will give LTA incentive to shed off the branches to accommodate services 66, 67, 700, 960. LTA is just waiting for the right time and need to do it.
Sure that SMRT will move into DDs. They have to or else their operations will be very difficult. While SBST is expanding, SMRT can't just because bendy buses are obstructing the expansions, and in every ways.
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Originally posted by SBS 1000U:
Sure that SMRT will move into DDs. They have to or else their operations will be very difficult. While SBST is expanding, SMRT can't just because bendy buses are obstructing the expansions, and in every ways.
Won't argue with you too much about it... Haiz...
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Originally posted by TIB868X:
SMRT should retain bendies for their feeders which has served them very well for many years. SMRT should get double deckers for their trunk services which don't have any height limits. Retain bendies for trunk services which have height limits like 67(?). For svc like 67 or 169 maybe can mix DD and bendy because not all commuters are long-haul ones and may just want to alight after a few stops, making them unwilling to go upstairs. for trunk-feeder hybrid like 962 or 859, i think its best stick with bendy
wow you guys are busting your nuts over this. if smrt operate bendy, so be it. if smrt gets dds, good for them. if smrt operates both, best of both worlds.
Haha very well said..I cant agree more to that.
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Originally posted by SBS 1000U:
I think it is better to get the model providing that kind of power but using engines less than 10 litres. Think of the road tax and fuel comsumption and the related cost. Now fuel not cheap too.If you do not know what you're talking about, please do not make such assumptions.
In practise, there is a lot that can affect the performance and fuel economy of a city bus (e.g. weight / load, topography, engine design, maintenance, driver training / driving style). There is a very important relationship between the engine and the transmission that affects the engine speed at any given road speed. It is therefore perfectly possible for bus with a small displacement engine to use more fuel than a bus fitted with a large displacement engine simply because it is working at non-optimal engine speeds when cruising at important road speeds.
You sound like a typical 'fleet manager' who has never been involved with buses or understand the relationship of power and torque outputs of an engine vs. displacement.
Yes, it is perfectly possible for a small displacement engine to make similar peak power and torque figures compared to a large displacement engine, but at what cost? You need a larger turbocharger capable of supplying higher boost pressure to the engine (read: slower transient throttle response and higher boost threshold), larger cooling system to handle the increased heat rejection, stronger internal engine components in order to cope with the higher operating pressure, and possibly shorter servicing intervals due to the engine operating at closer to its physical limitations. Furthermore, a small displacement engine produces low torque at the most important low engine speeds where the turbocharger is inefficient, which is not ideal for driveability, meaning that in order for the bus to accelerate at a sufficient rate, you need to keep the engine speeds high which in turn means unnecessary noise and vibration. Larger engines not only produce high power and torque at lower engine speeds, but also provide a larger torque band - a window of engine speeds where peak torque is available under foot. This ensures less gearchanges required even in harsh topographies and the possibility of using a taller final drive ratio, further keeping engines speeds and therefore noise and vibration levels lower.
So in short, smaller engines DO NOT automatically mean lower fuel consumption.
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Originally posted by SBS 1000U:
Sure that SMRT will move into DDs. They have to or else their operations will be very difficult. While SBST is expanding, SMRT can't just because bendy buses are obstructing the expansions, and in every ways.
How sure? I won't correct you but that's really a gamble too much. (I wonder what you will do if SMRT orders more bendies
)Anyway, I don't mind DDs on SMRT, as long as they still remain useful
Don't want to come back to another stupid debate, so yeah.
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Originally posted by Powered_By_CNG:
If you do not know what you're talking about, please do not make such assumptions.
In practise, there is a lot that can affect the performance and fuel economy of a city bus (e.g. weight / load, topography, engine design, maintenance, driver training / driving style). There is a very important relationship between the engine and the transmission that affects the engine speed at any given road speed. It is therefore perfectly possible for bus with a small displacement engine to use more fuel than a bus fitted with a large displacement engine simply because it is working at non-optimal engine speeds when cruising at important road speeds.
You sound like a typical 'fleet manager' who has never been involved with buses or understand the relationship of power and torque outputs of an engine vs. displacement.
Yes, it is perfectly possible for a small displacement engine to make similar peak power and torque figures compared to a large displacement engine, but at what cost? You need a larger turbocharger capable of supplying higher boost pressure to the engine (read: slower transient throttle response and higher boost threshold), larger cooling system to handle the increased heat rejection, stronger internal engine components in order to cope with the higher operating pressure, and possibly shorter servicing intervals due to the engine operating at closer to its physical limitations. Furthermore, a small displacement engine produces low torque at the most important low engine speeds where the turbocharger is inefficient, which is not ideal for driveability, meaning that in order for the bus to accelerate at a sufficient rate, you need to keep the engine speeds high which in turn means unnecessary noise and vibration. Larger engines not only produce high power and torque at lower engine speeds, but also provide a larger torque band - a window of engine speeds where peak torque is available under foot. This ensures less gearchanges required even in harsh topographies and the possibility of using a taller final drive ratio, further keeping engines speeds and therefore noise and vibration levels lower.
So in short, smaller engines DO NOT automatically mean lower fuel consumption.
Good explanation but there is no need to debate with SBS1000U, otherwise later flamewar.
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Originally posted by TIB1138M:
How sure? I won't correct you but that's really a gamble too much. (I wonder what you will do if SMRT orders more bendies
)Anyway, I don't mind DDs on SMRT, as long as they still remain useful
Don't want to come back to another stupid debate, so yeah.
Gamble? I won't hope much, given their state of their operations right now. I would certainly discourage SMRT to do so (buy new bendies) if they wants to be more efficient which they have to in line with the new BSEP.Originally posted by Powered_By_CNG:If you do not know what you're talking about, please do not make such assumptions.
In practise, there is a lot that can affect the performance and fuel economy of a city bus (e.g. weight / load, topography, engine design, maintenance, driver training / driving style). There is a very important relationship between the engine and the transmission that affects the engine speed at any given road speed. It is therefore perfectly possible for bus with a small displacement engine to use more fuel than a bus fitted with a large displacement engine simply because it is working at non-optimal engine speeds when cruising at important road speeds.
You sound like a typical 'fleet manager' who has never been involved with buses or understand the relationship of power and torque outputs of an engine vs. displacement.
Yes, it is perfectly possible for a small displacement engine to make similar peak power and torque figures compared to a large displacement engine, but at what cost? You need a larger turbocharger capable of supplying higher boost pressure to the engine (read: slower transient throttle response and higher boost threshold), larger cooling system to handle the increased heat rejection, stronger internal engine components in order to cope with the higher operating pressure, and possibly shorter servicing intervals due to the engine operating at closer to its physical limitations. Furthermore, a small displacement engine produces low torque at the most important low engine speeds where the turbocharger is inefficient, which is not ideal for driveability, meaning that in order for the bus to accelerate at a sufficient rate, you need to keep the engine speeds high which in turn means unnecessary noise and vibration. Larger engines not only produce high power and torque at lower engine speeds, but also provide a larger torque band - a window of engine speeds where peak torque is available under foot. This ensures less gearchanges required even in harsh topographies and the possibility of using a taller final drive ratio, further keeping engines speeds and therefore noise and vibration levels lower.
So in short, smaller engines DO NOT automatically mean lower fuel consumption.
Thanks for the info.
I may not be a tech guru in engines but in today's automobile industry, many auto manufacturers are downsizing car engines while producing adequate power to propel the car. In fact, due to motors integrating with electrical hybrid designs and turbochargers, the future is about such technologies, while maintaining low fuel consumptions and keep it small.
As for our road tax structure, it simply discourage our operators to buy big engine capacity buses. Thus looking into smaller engines that provides acceptable performance while going in line with the government green policies.
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Originally posted by SBS 1000U:
I may not be a tech guru in engines but in today's automobile industry, many auto manufacturers are downsizing car engines while producing adequate power to propel the car. In fact, due to motors integrating with electrical hybrid designs and turbochargers, the future is about such technologies, while maintaining low fuel consumptions and keep it small.
As for our road tax structure, it simply discourage our operators to buy big engine capacity buses. Thus looking into smaller engines that provides acceptable performance while going in line with the government green policies.
The downsizing of engines in passenger cars may be acceptable considering naturally aspirated engines are currently the norm and the maximum weight likely to require shifting is unlikely to exceed 2,000kg, but when you're dealing with commercial vehicles where turbocharged diesel engines are already the norm, you're dealing with a completely different kettle of fish.
There are times where additional tax expenditure is unlikely to dictate decisions made by an operator. The extra money spent on road tax brings the benefit of higher levels of passenger comfort (i.e. lower complaints due to rough gearchanges or high noise / vibration levels) and decreased downtime and operating costs due to longer life of components that are put under lower levels of stress.
Going back to fuel consumption, just to give you an idea, a Mercedes-Benz OC 500 LE with a ZF 6 AP 1400 B TopoDyn gearbox and a 12-litre OM 457 hLA engine with 299 PS returns similar fuel consumption figures to a Volvo B7RLE with a Voith D864.5 SensoTop gearbox and a 7.1-litre D7E engine with 290 PS. The OC 500 LE is clearly more powerful at low engine speeds and has kickdown function whereas the B7RLE is the weaker performer especially below 1100rpm and does not have kickdown function.
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Originally posted by Powered_By_CNG:
The downsizing of engines in passenger cars may be acceptable considering naturally aspirated engines are currently the norm and the maximum weight likely to require shifting is unlikely to exceed 2,000kg, but when you're dealing with commercial vehicles where turbocharged diesel engines are already the norm, you're dealing with a completely different kettle of fish.
There are times where additional tax expenditure is unlikely to dictate decisions made by an operator. The extra money spent on road tax brings the benefit of higher levels of passenger comfort (i.e. lower complaints due to rough gearchanges or high noise / vibration levels) and decreased downtime and operating costs due to longer life of components that are put under lower levels of stress.
Going back to fuel consumption, just to give you an idea, a Mercedes-Benz OC 500 LE with a ZF 6 AP 1400 B TopoDyn gearbox and a 12-litre OM 457 hLA engine with 299 PS returns similar fuel consumption figures to a Volvo B7RLE with a Voith D864.5 SensoTop gearbox and a 7.1-litre D7E engine with 290 PS. The OC 500 LE is clearly more powerful at low engine speeds and has kickdown function whereas the B7RLE is the weaker performer especially below 1100rpm and does not have kickdown function.
I believe it will come to a time that commercial vehicles will downsize their engines soon. The car engine technologies are the test bed for any technological advnaces in the past as they are smaller and easier to implement and test out before using these technologies for bigger machines. Once auto manufacturers are able to produce efficient and lasting smaller engines which can produce adequate performance and cleaner engines, they will intorduce it to bigger vehicles. As our fuel sources are rapidly depleting and booming world population, plus awareness of greener enviroment globally, this technological advancement has to be improved.
Bus manufacturers have also been trying to downsizing engines, offering smaller engines with adequate performance. Technologies might be premature but these will be improved as time passes.
In Singapore context, we are moving more into greener awareness. The implementation of EURO IV requirements in a few years time will certainly affect our bus operators' decisions, which they are even looking into EURO IV and beyond. However as engines move beyong EURO IV, bus operators are making smaller efficient engines for stricter emission standards too. How many options they have???
Lastly, our government may also implement carbon tax soon, which bus operators should also consider this as well. Road tax is another issue to consider. Right now, our bus operators are beginning to use smaller engines which are comfortable as well.
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Originally posted by TIB1218R:
So we expect to see high capacity bus to have more than 320hp and above 10000cc?
Doesnt matter about the cubic capacity,Be it 8000cc,9000cc as long power rating must be 320hp above.The last time we discuss with the senior tech power n torque for bendies/DDs is important.MAN NL323 already 320hp/1600nm so they cannot expect DD/Bendies have lower power rating than the SDs.Enviro 500 is good,8900cc but with 335hp/1600nm.Too bad the 13.7m MAN ND363 are not considered.
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Originally posted by d143b2:
there is OC500UA, but i doubt it would bring in, there are much better bendies out there
bendies would be needed on 902
some services need full bendy perms
Scania KUA not counted? -
Originally posted by iveco:
Scania KUA not counted?KUA are fine
but i don't know whether they bring in or not ...
but i see many KUBs already ... so many can see until sian also ...
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KUA is low entry. NUA is low floor. NUA will be the the desired configuration if Scanias are ordered.
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Originally posted by SBS 1000U:
In Singapore context, we are moving more into greener awareness. The implementation of EURO IV requirements in a few years time will certainly affect our bus operators' decisions, which they are even looking into EURO IV and beyond. However as engines move beyong EURO IV, bus operators are making smaller efficient engines for stricter emission standards too. How many options they have???
A bigger engine may not always be less clean than a 'smaller' engine. Take the OC500LE which displaces ~12000cc and the KUB which displaces ~8900cc as an example...
IMO, SCR is the way to go to reduce emissions, not EGR, which is the direction Mercedes is going. The pros and cons of SCR outweigh the pros and cons of EGR. With SCR, there is little to no sacrifice needed to the engine displacement/size, which may comprimise performance. and I've seen much more smoke and soot exiting the KUB (and MAN's) EGR engine than the B9TL WEG2 and OC's SCR engine....
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Originally posted by SBS 1000U:
As for our road tax structure, it simply discourage our operators to buy big engine capacity buses. Thus looking into smaller engines that provides acceptable performance while going in line with the government green policies.
and how much do bureaucrats know about the relationship between engine capacity, performance and savings over the course of the bus lifespan? "acceptable" performance with lower tax rates may seem very attractive now but what operators should go for are savings in the long run while not comprimising on performance.
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Now bus manufacturers also keen to decrease their engine cc.Volvo alrdy starts with B5 replacing B7 and B8 replacing B9,duh.AD also got new ranges of euro 6 engine starting from 4500cc for citybuses.Left with Scania.Will be great if SMRT purchase K360 DD or NUA
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Originally posted by carbikebus:
Now bus manufacturers also keen to decrease their engine cc.Volvo alrdy starts with B5 replacing B7 and B8 replacing B9,duh.AD also got new ranges of euro 6 engine starting from 4500cc for citybuses.Left with Scania.Will be great if SMRT purchase K360 DD or NUA
Please check your facts before posting. The 5-litre engine is for HYBRID BUSES ONLY. The 8-litre Euro VI engine replaces the 7 and 9-litre Euro V engines.