Hydrokinetic DMUs - can you wheelspin them past 2nd?

[Egg Centric]

If you handle a DMU like a 158 atrociously and just whack it into step 7 on something seriously slippy, can you get the wheels spinning so quickly that the box changes into 2nd and continues accelerating them up to the top speed of the unit, or is that impossible because during the "lockup" there's no power applied and the wheel gets back to actual speed?

(Hope this question makes sense - I'm not a mechanical engineer so may be using the wrong terms)

(The inspiration for this question is me managing to do this in a 142 in a train simulator and wondering if it could be true to life)

 

[driverd]

If you handle a DMU like a 158 atrociously and just whack it into step 7 on something seriously slippy, can you get the wheels spinning so quickly that the box changes into 2nd and continues accelerating them up to the top speed of the unit, or is that impossible because during the "lockup" there's no power applied and the wheel gets back to actual speed?

(Hope this question makes sense - I'm not a mechanical engineer so may be using the wrong terms)

(The inspiration for this question is me managing to do this in a 142 in a train simulator and wondering if it could be true to life)

Not on a 158 as these have wheel spin protection (WSP) and will automatically cut the power when a spin is detected.

The same is fitted to everything 150 and above and I'm pretty sure pacers had it too (it's a good few years since I drove one).

EDIT: I'm 99.9% sure you couldn't spin a pacer either. You'd get gear box fault light (either local or train) and the power cuts. You'd then need to notch back the power to prevent doing the same thing again. It may well have been a modification though, so train sim may be accurate to the "as built" pacer (Though, if it's the latest AP model, there's a few inaccuracies I've spotted to look out for).

Theoretically, yes, you could get fluid coupled if there was no WSP - the gearbox is literally a vessel that progressively fills with oil (so no power drop during the gearing up process), though I suspect you'd have wheelspun all the way through the rail/removed your traction tyres before you got there.

 

[LowLevel]

Not on a 158 as these have wheel spin protection (WSP) and will automatically cut the power when a spin is detected.

The same is fitted to everything 150 and above and I'm pretty sure pacers had it too (it's a good few years since I drove one).

EDIT: I'm 99.9% sure you couldn't spin a pacer either. You'd get gear box fault light (either local or train) and the power cuts. You'd then need to notch back the power to prevent doing the same thing again. It may well have been a modification though, so train sim may be accurate to the "as built" pacer (Though, if it's the latest AP model, there's a few inaccuracies I've spotted to look out for).

Theoretically, yes, you could get fluid coupled if there was no WSP - the gearbox is literally a vessel that progressively fills with oil (so no power drop during the gearing up process), though I suspect you'd have wheelspun all the way through the rail/removed your traction tyres before you got there.

You can certainly spin 15x up. They're particularly prone to it with their single power bogie per car, particularly 158s, though it does generate transmission faults if they slip too long - 153s would go for so long then get a latched on transmission fault that needed a fitter to clear it though if I remember rightly it didn't actually affect performance if you ignored it.

As a guard of many years on Sprinters I've often stood at the number 2 end of the saloon wondering just when the driver is going to shut off when they're spinning off the clock hearing the power bogies screaming away rather than just let them keep spinning up.

The wheel slip protection on them is crap - they just shut off briefly then stick the power back on and keep spinning merrily away.

(Originally posted some stuff about wheel slide protection having misread the gist of the post).

 

[driverd]

You can certainly spin 15x up. They're particularly prone to it with their single power bogie per car, particularly 158s, though it does generate transmission faults if they slip too long - 153s would go for so long then get a latched on transmission fault that needed a fitter to clear it though if I remember rightly it didn't actually affect performance if you ignored it.

From the front end, it jolts and shakes a bit and then dips the power. It doesn't move much and will just keep doing that until you move the power back (admittedly, I didn't like providing a rough ride so would ease off reasonably quickly). Interesting to hear it comes across so rough in the middle!

As a guard of many years on Sprinters I've often stood at the number 2 end of the saloon wondering just when the driver is going to shut off when they're spinning off the clock hearing the power bogies screaming away rather than just let them keep spinning up.

The wheel slip protection on them is crap - they just shut off briefly then stick the power back on and keep spinning merrily away.

They definitely don't actually put much power down, though. You get a clear difference in performance at the front end. I'm surprised to hear how lazy some drivers are with the power!

Edit: Just to clarify, I'm not saying you can't spin up a 15x, just that you can't spin it anywhere near enough to get the gearbox fluid coupled. The train stops you way before that point. You'll get a bit of a spin, but then an immediate dip in power.

 

[Egg Centric]

Edit: Just to clarify, I'm not saying you can't spin up a 15x, just that you can't spin it anywhere near enough to get the gearbox fluid coupled. The train stops you way before that point. You'll get a bit of a spin, but then an immediate dip in power.

Yup, that's my question. Thanks. "In game" I was doing this on the "2 speed" 142s - any idea if the original "4 speed" 142s could get into second?

Presumably nothing at all stopping anyone putting a 1st gen DMU into 2nd or higher gear...

(Also thanks @LowLevel even if I didn't express myself properly that's useful "colour"!)

(Also here is why it's perfectly reasonable for me to drive like that. Anyone not in the STS wouldn't understand)