Stated maximum speed -safe maximum or absolute maximum?

[cjmillsnun]

I think we have to be careful here. With the exception of sports/exotic cars, they are not tested for thousands of miles at the speeds the engine is capable of achieving. All trains are tested extensively at their rated maximum speed and beyond before being permitted in public service.

Sorry that's complete rubbish. The tests a car goes through in the pre-production stage includes thousands of miles of high speed running at private test tracks throughout the world. Places like the Millbrook proving ground or MIRA are used in the UK.

Cars are very much designed to reach their maximum speed and cruise there. The main reason why people don't are speed limits and the cost of fuel.

 

[notadriver]

Sorry that's complete rubbish. The tests a car goes through in the pre-production stage includes thousands of miles of high speed running at private test tracks throughout the world. Places like the Millbrook proving ground or MIRA are used in the UK.

Cars are very much designed to reach their maximum speed and cruise there. The main reason why people don't are speed limits and the cost of fuel.

Yes the prototypes of course but every single model off the line ? Has my partners little Hyundai - her exact one - been tested at 105 mph? I think not.

 

[455driver]

Yes the prototypes of course but every single model off the line ? Has my partners little Hyundai - her exact one - been tested at 105 mph? I think not.

Lend it to me for an hour and I will have a go for you!

 

[507 001]

Yes the prototypes of course but every single model off the line ? Has my partners little Hyundai - her exact one - been tested at 105 mph? I think not.

No but neither will have every ferrari or lamborghini or even HST power car?!

Before the cars are even let loose at the proving ground the design is put through its paces using CAD/CAM simulations and endurance testing which could involve constant running of a prototype engine at maximum RPM until it breaks or constantly running up to full speed and back to idle, again till something breaks!

I'd be quite happy running my focus up to a ton and leaving it there for a few hours!

 

[cjmillsnun]

Yes the prototypes of course but every single model off the line ? Has my partners little Hyundai - her exact one - been tested at 105 mph? I think not.

No of course it hasn't, but how many locos or units (that exact one) are fully tested before entering service?

Most aren't. For example many class 66 locos were commissioned on the dockside and went straight into service.

 

[TDK]

I occasionally drive the Northern "staff train" from Manchester to Preston (Via WCML) in the early hours. It quickly gets up to 75 but after a while the transmission "gears up" or whatever it does and a load of strain is taken off the engine etc. Sometimes cruising at 75mph is better than start/stop as mentioned above!

Should add it's a 153!

The gearbox on a 153 is a voith and will go from torque converter (@2100rpm) at there abouts to fluid coupling at about 45mph, the revs build again to about 2000rpm at 75mph, this is when the revs drop, if you are driving a 153 you should know this stuff as it is part of your traction course!
--- old post above --- --- new post below ---

In what sense?

The maximum speed of a car could be 120mph but it is not permitted to travel at over 70mph on UK roads. Likewise if the maximum speed of a train could be 90mph but it's not allowed to travel at over 75mph on National Rail track.

The top speed of a train is governed to the braking capabilities of the unit. Anything over 75mph in a 75mph unit should not be attempted as a driver.
--- old post above --- --- new post below ---

No of course it hasn't, but how many locos or units (that exact one) are fully tested before entering service?

Most aren't. For example many class 66 locos were commissioned on the dockside and went straight into service.

I thought all new trains had to have proving runs before they could enter service. I know the 377's did and so did the 175's. I belive it is in the region of 1000 miles per unit?

 

[notadriver]

I don't know about the locomotives but I also thought all new trains were subject to proving runs without failures... 2000 miles in some cases and each individual unit ( i drive Electrostars) will go to their rated speed plus 10%. I will be legally cruising at 90 - 100 mph in my train. How many car drivers do that speed for any sustained period of time in this country?

 

[monty9120]

I don't know about the locomotives but I also thought all new trains were subject to proving runs without failures... 2000 miles in some cases and each individual unit ( i drive Electrostars) will go to their rated speed plus 10%. I will be legally cruising at 90 - 100 mph in my train. How many car drivers do that speed for any sustained period of time in this country?

i wonder say a fair few high distance commuters to be honest

 

[asylumxl]

Lend it to me for an hour and I will have a go for you!

Might as well aim a bit higher. Know a few fast roads with downhill stretches....

 

[Bedpan]

My first car was an old 803cc Morris Minor, and that did 80mph, but only for a few miles and then one of the big ends went. I always thought that cars had a tomp speed - put your foot hard down on the flat, leave it there, and see what speed you achieve, and a maximum cruising speed which it can do safely without causing damage and which is presumably more akin to the railway loco/multiple unit situation where we know that units are tested at a speed 10% above their stated maximum. The top speed must by definition be at least the maximum permitted speed plus the 10% overspeed capability.

 

[edwin_m]

I don't know how they managed to test a 170 at 100mph plus 10% as they take forever to reach 100 on level track. Must have found a very long hill somewhere I suppose.

 

[matchmaker]

As an old f**t, I seem to remember a 156 running on a publicity trip (soon after introduction) between Leeds and York being reported in the railway media to have reached something like 93MPH!

I timed (by stopwatch and mileposts) a 156 at 86mph between Stirling and Larbert once - many years ago!

 

[cjmillsnun]

I don't know about the locomotives but I also thought all new trains were subject to proving runs without failures... 2000 miles in some cases and each individual unit ( i drive Electrostars) will go to their rated speed plus 10%. I will be legally cruising at 90 - 100 mph in my train. How many car drivers do that speed for any sustained period of time in this country?

A lot more than you think... They seem to think that the road is their own personal raceway. I'm sure I have been passed by people doing over 100MPH

 

[dcsprior]

A lot more than you think... They seem to think that the road is their own personal raceway. I'm sure I have been passed by people doing over 100MPH

Although you do occasionally see cars doing >100mph, it is quite rare as at that speed drivers are risking an instant ban if caught.

Also, almost every car speedometer over-reads. For long journeys we use an GPS speed app, which sounds an alarm at 79mph (70 + 10% + 2mph) and at that point the car's speedo is reading around 95. Other drivers do overtake at this speed, but that doesn't mean they're doing >100

 

[notadriver]

Although you do occasionally see cars doing >100mph, it is quite rare as at that speed drivers are risking an instant ban if caught.

Also, almost every car speedometer over-reads. For long journeys we use an GPS speed app, which sounds an alarm at 79mph (70 + 10% + 2mph) and at that point the car's speedo is reading around 95. Other drivers do overtake at this speed, but that doesn't mean they're doing >100

Thats quite a large discrepancy in this case - a true 79 mph equating to an indicated 95. In my car 70 mph on my GPS is about 74 mph on the speedometer. Car speedos are not allowed to under read by law so i guess someone doing an indicated 100 could only be doing a true 90 mph. But the train speedometer is accurate to within a few mph. I did a check when I was a conductor on a few units.

 

[asylumxl]

Although you do occasionally see cars doing >100mph, it is quite rare as at that speed drivers are risking an instant ban if caught

Check the southern part of the M1 late at night and then tell me if you think it's rare.

It's worth noting that a few lines down here (WCML, MML off my head) run parallel to the M1. It's not rare to see a car maintaining a similar speed to a Meridian on the MML.

 

[GB]

deleted.

 

[northwichcat]

Car speedos are not allowed to under read by law so i guess someone doing an indicated 100 could only be doing a true 90 mph. But the train speedometer is accurate to within a few mph. I did a check when I was a conductor on a few units.

Your speedo has to be in working order when new and to pass it's MOT. Legally if it's broken you aren't allowed to put your car on the road except to take it to a pre-arranged appointment at a garage to get it fixed. However, you wouldn't actually notice if it was showing 70mph when you're doing 72mph until you next took the car for an MOT or service.

 

[dcsprior]

Your speedo has to be in working order when new and to pass it's MOT.

Yeah, but over-reading doesn't mean its not in working order (under-reading does however)

 

[Wikipedia]

I think car speedos are allowed to over read by 10% and under by 0%!!

 

[LE Greys]

Check the southern part of the M1 late at night and then tell me if you think it's rare.

It's worth noting that a few lines down here (WCML, MML off my head) run parallel to the M1. It's not rare to see a car maintaining a similar speed to a Meridian on the MML.

I think I can beat that. A section of LGV Nord runs alongside the A1 Autoroute south of Lille. I've been in a Eurostar on that section that was keeping up with an Italian-reg Ferrari (probably an F50) that must have been trying to race the train. I lost sight of it after a while, mostly because of an enormous traffic jam. All this time we were at or near 186mph.

 

[142056]

Compared to a Satnav/GPS a car speedometer always over-reads. I find the difference increases with the speed.
My Nissan will say 80mph on the speedometer wheras the satnav will say 73mph; however the same satnav in a BMW where the car speedometer says 80mph the satnav says 77mph.
Similar age cars too, so I guess the manufacturing differs. I can't imagine the speedometers are adjusted as much after new as train's speedometers are, either.
And those that talk about the southern end of the M1 etc, try the M6 north of Preston and then the A74(M) for speeding. The latter was once termed 'Britain's fastest road' with averages speeds of well above 70.

 

[millemille]

Your speedo has to be in working order .... to pass it's MOT.

No it doesn't.

A speedometer has to be fitted, appear in good condition and illuminate but the function is in no way tested.

The function & accuracy of a speedometer is only subject to scrutiny when the manufacturer puts a mass produced car through Type Approval or when an individual puts a one-off machine though Single Vehicle Approval.

 

[507 001]

My first car was an old 803cc Morris Minor, and that did 80mph, but only for a few miles and then one of the big ends went. I always thought that cars had a tomp speed - put your foot hard down on the flat, leave it there, and see what speed you achieve, and a maximum cruising speed which it can do safely without causing damage and which is presumably more akin to the railway loco/multiple unit situation where we know that units are tested at a speed 10% above their stated maximum. The top speed must by definition be at least the maximum permitted speed plus the 10% overspeed capability.

Your car will pretty much keep going til it runs out of gears, simple as that*.

Engines are tested for hours/days/weeks at full revs on test rigs before they even get near a car.


*thats not me saying that running at higher speeds won't increase the risk of a failure btw!

 

[northwichcat]

No it doesn't.

A speedometer has to be fitted, appear in good condition and illuminate but the function is in no way tested.

According to the Highway Code the speedometer along with things including the windscreen washers, windscreen wipers and horn MUST be in good working order for your car to be roadworthy so I assumed they would be all checked as part of an MOT.

 

[A-driver]

Check the southern part of the M1 late at night and then tell me if you think it's rare.

It's worth noting that a few lines down here (WCML, MML off my head) run parallel to the M1. It's not rare to see a car maintaining a similar speed to a Meridian on the MML.

I have been overtaken by cars on the A505 between baldock and Royston before when doing 90 in a train! And sections of that road are single carriage way to I believe.

As for testing trains at higher speeds, they are tested far higher than speed+10. Perhaps not each individual unit but prototypes are. A fitter at Selhurst told me that electro stars were tested with air suspension isolated at 140mph so I assume they were tested even higher with full suspension.

 

[455driver]

According to the Highway Code the speedometer along with things including the windscreen washers, windscreen wipers and horn MUST be in good working order for your car to be roadworthy so I assumed they would be all checked as part of an MOT.

As the car doesnt leave the garage during an MOT and it will only be doing about 2 or 3mph on the brake rollers how is the speedo tested?

 

[TDK]

As the car doesnt leave the garage during an MOT and it will only be doing about 2 or 3mph on the brake rollers how is the speedo tested?

Some speedo's now a days can be tested electronically and this is how many train speedo's are tested however not for an MOT!

 

[the sniper]

My Nissan will say 80mph on the speedometer wheras the satnav will say 73mph

I wonder whether this is a Renault-Nissan Alliance standard thing, as my Clio is exactly the same.

 

[notadriver]

I think I can beat that. A section of LGV Nord runs alongside the A1 Autoroute south of Lille. I've been in a Eurostar on that section that was keeping up with an Italian-reg Ferrari (probably an F50) that must have been trying to race the train. I lost sight of it after a while, mostly because of an enormous traffic jam. All this time we were at or near 186mph.

Very interesting. Given a completely clear autoroute from Calais to Paris surely the most hardened car fanatic must admit that the Ferrari wouldn't be able to keep up with the Eurostar all the way to Paris?

High speed rail competes against air travel for trips up to around 3 hours. I'd feel far safer in a professionally driven train cruising at 300 kph than with some amateur who thinks he can race a train at that speed lol