Trains cut engines to save fuel

M Platting wrote:
> I use these trains virtually every day and, so far, haven't noticed
> anything adverse in First Transpennine's performance:

Well, ye canna change the laws of phusics!

It seems to have been reported, on the radio at least, as something
that’s been implemented by means of an instruction to drivers when of
course it’s a somewhat sophisticated engine management system.

Cue, lots of discussion about is it safe to do the same in your car
(it isn’t particularly when steering locks are considered) and little
discussion about the details of the TPX trains or the route
characteristics, which is a bit of a shame.

Like previous generations of TP services the route characteristics
(i.e. straight up then straight back down) has led to its trains being
somewhat blessed with horsepower.

Think back to the TP DMUs that were similarly so equipped.

On Sep 3, 6:18 pm, allan tracy <thunderbird57...@m> wrote:

> Cue, lots of discussion about is it safe to do the same in your car
> (it isn’t particularly when steering locks are considered)

It's perfectly easy to switch off the engine without engaging the
steering lock. What isn't quite so easy is maintaining pressure in
the power steering (virtually universal these days, and electric power
steering a la Corsa is unusual) and even more importantly the
brakes.

I'm reasonably strong (I can dead-lift 120kg, substantially more than
my body weight) and on the one occasion I managed to stall my Passat
the steering was close to solid. Modern suspension geometries result
in the front of the car being lifted slightly as the steering goes out
from dead centre, and power steering encourages two turns lock-to-
lock.

Stopping an ABS-equipped car with no power assistance is likewise a
major undertaking, and most people would be either unable to, or
unwilling to believe you need to, press the pedal that hard.

ian

On Sep 3, 9:35 pm, a...@aber.ac.uk (Andrew Robert Breen) wrote:
> In article <47d55312-930e-4565-a26c-a920d64ac...@a2g2000prm..com>,
>
>  <i.g.bat...@batten.eu.org> wrote:
> >On Sep 3, 7:47 pm, a...@aber.ac.uk (Andrew Robert Breen) wrote:
>
> >> Perfectly safe in a Proper SAAB.
>
> >What's proper?  I've owned 96, 99, 900, 9000 and 9-3, and I wouldn't
>
> I was being deliberately obtuse and thinking of the 95 aand 96, with lock
> on reverse gear and the freewheel :)

Well, the same applies on all 4-stroke Saabs apart from 9000s: unlike
a steering lock, which will engage simply on key position, the reverse
lock requires you to select reverse and _then_ turn the key fully anti-
clockwise.

[[ For those that care, the reason why most Saabs have the key on the
floor is that in the 1960s, steering locks weren't thought of, but
Saab decided to leverage their column shift and install a reverse-gear
lock as an anti-theft feature. That arrived in the 95 and 96, with
the ex-Ford V4 engine. When the gearshift moved to the floor in the
99 steering locks were still uncommon, so Saab took the key down there
and continued with the reverse lock. Autos lock in park. The
exception is the 9000, for a variety of reasons. It's not an
unalloyed blessing: it means the key slot faces upwards, so
contamination of the locks with dirt is more common that in other cars
--- dirt falls on the keyway guard, you put the key in, the dirt falls
inside. And it means that the plastics around the lock get scratched
up by anything else on the same keyring, and on some models it gets a
bit awkward squeezing the handbrake, those horrid modern centre boxes,
and room for your arm to turn the key into the same space. ]]

> I was mildly surprised by just how big a difference it made when I
> compared the two approaches in the 9000.

It's another good reason to drive an auto. I drive a DSG diesel
(Skoda Octavia) and my wife drives a Petrol Auto (Saab 9-3), and of
course both tend to overrun in top gear: you lift off at any speed and
it tends to change up. Which means that you can coast up to red
lights on slight engine braking, using no fuel, confident that if you
need to accelerate it'll immediately drop to the right gear. In a
manual that's harder, and in a diesel especially so because of the
higher compression ration and narrower torque band.

ian