We've just managed to get an extra 20hp

[eisenach]

I'm not sure this is the right place for this post, but anyway ...

I met my wife off the 16.40 Holyhead train at Leominster yesterday. It was formed of a 2 car 175, with 175003 on the front. She had got on at Newport. It was 15 minutes late arriving at Leominster and was going to be terminated at Chester. She had an interesting tale to tell.

At some point just before Hereford, a somewhat tired train manager / guard sat for a moment at her table and said something like:

It's a bit touch and go. We're an engine down and we were wondering whether to terminate at Newport, but the driver had decided to go for it. They'd managed to get an extra 20hp out of the remaining engine and now that they'd cleared the slog up to Hereford it looked like they were going to make it, though the driver was glad he was handing over at Shrewsbury because he was rather frazzled.

It was obviously losing time because the delay on the display whilst I was waiting on the platform went up from 12 to 15 minutes. Not bad really. It left at about 16.57 and the train behind, the 17.07 to Manchester must have been catching up, but I guess it managed to make it to Shrewsbury without holding it up too much.

I didn't know you could uprate the engine on the go. Does it involve remapping the engine like you would on a car ? Can the driver just press a button to do it or is it more complicated than that ?

It was rather a good effort by all concerned, I think. Well done !

 

[Ash Bridge]

I'm not sure this is the right place for this post, but anyway ...

I met my wife off the 16.40 Holyhead train at Leominster yesterday. It was formed of a 2 car 175, with 175003 on the front. She had got on at Newport. It was 15 minutes late arriving at Leominster and was going to be terminated at Chester. She had an interesting tale to tell.

At some point just before Hereford, a somewhat tired train manager / guard sat for a moment at her table and said something like:

It's a bit touch and go. We're an engine down and we were wondering whether to terminate at Newport, but the driver had decided to go for it. They'd managed to get an extra 20hp out of the remaining engine and now that they'd cleared the slog up to Hereford it looked like they were going to make it, though the driver was glad he was handing over at Shrewsbury because he was rather frazzled.

It was obviously losing time because the delay on the display whilst I was waiting on the platform went up from 12 to 15 minutes. Not bad really. It left at about 16.57 and the train behind, the 17.07 to Manchester must have been catching up, but I guess it managed to make it to Shrewsbury without holding it up too much.

I didn't know you could uprate the engine on the go. Does it involve remapping the engine like you would on a car ? Can the driver just press a button to do it or is it more complicated than that ?

It was rather a good effort by all concerned, I think. Well done !

I'm only guessing of course, but could more power be diverted for traction purposes by shutting down various systems such as heating, aircon etc.?

 

[Deepgreen]

"She'll nae take much more o' this, Captain!"

 

[Bletchleyite]

I'm only guessing of course, but could more power be diverted for traction purposes by shutting down various systems such as heating, aircon etc.?

I'd imagine so, Voyagers are capable of doing this automatically, and in the early days often used to automatically lose bits of lighting etc if the driver tried to take off a bit quick, with it returning once he backed off.

They might well have been on the phone to Alstom who could advise them precisely what to trip out to do that manually.

 

[ac6000cw]

"She'll nae take much more o' this, Captain!"

Time to polish the dilithium crystals maybe?

But back on Earth, I imagine the extra 20hp for traction came from shedding as much of the auxiliary 'hotel' load as possible.

 

[eisenach]

Ah, I hadn't thought of shutting other demands down, though I think I like the dilithium crystal polishing better !

 

[JN114]

175s aren't Diesel Electric so hotel power isn't going to affect how much power the traction motors get because it doesn't have any!

 

[hwl]

175s aren't Diesel Electric so hotel power isn't going to affect how much power the traction motors get because it doesn't have any!

But reducing alternator load will mean there is more available mechanical power out of the engine.

On a car having headlights, blowers and other stuff on in winter reduces you fuel economy because the alternator load has increased to provide more electrical power...

 

[Deepgreen]

But reducing alternator load will mean there is more available mechanical power out of the engine.

On a car having headlights, blowers and other stuff on in winter reduces you fuel economy because the alternator load has increased to provide more electrical power...

Does the same principle not apply in other seasons?

 

[JN114]

But reducing alternator load will mean there is more available mechanical power out of the engine.

On a car having headlights, blowers and other stuff on in winter reduces you fuel economy because the alternator load has increased to provide more electrical power...

HVAC (Heating/Air Con) is the only system that would make a discernible difference in available engine power - Perhaps I underestimate ATW but I couldn't see one of our staff isolating HVAC just to gain a bit more performance for a late running one-engine only service on a cold January evening. Especially as you'd lose cab heat as well.

 

[hwl]

Does the same principle not apply in other seasons?

Yes - I was talking about average fuel economy but more noticeable in winter as there are more dark hours, it is colder (more blower and rear windscreen/mirror heater use) and the ability to charge/discharge the battery decreases with lower average temperatures.

 

[eisenach]

HVAC (Heating/Air Con) is the only system that would make a discernible difference in available engine power - Perhaps I underestimate ATW but I couldn't see one of our staff isolating HVAC just to gain a bit more performance for a late running one-engine only service on a cold January evening. Especially as you'd lose cab heat as well.

I'll ask my wife if she was cold !

 

[Bletchleyite]

I'll ask my wife if she was cold !

If it was cold, just losing the aircon would probably be good enough. Heating is just from waste engine heat, isn't it?

 

[DaleCooper]

20hp is 15kW, sounds a lot that way.

 

[DarloRich]

"She'll nae take much more o' this, Captain!"

Dilithium chamber at maximum, Captain! I've giv'n her all she's got captain, an' I canna give her no more.

 

[richa2002]

175s have an emergency switch which can activate more power in notch 4. In normal conditions, notch 3 & 4 are identical.

 

[eisenach]

175s have an emergency switch which can activate more power in notch 4. In normal conditions, notch 3 & 4 are identical.

Ah, so it is as simple as pressing a button .
Thanks.

 

[dgl]

175s have an emergency switch which can activate more power in notch 4. In normal conditions, notch 3 & 4 are identical.

We're loosing time we need more power, do whatever you can, shut off this divert power to that just do something,
I'm trying my best and have done all I can,
Well what's that
I Flicked this switch,
and...
well that's all I did

 

[NickBucks]

Lewis Hamilton's winter job perhaps ?

 

[najaB]

Lewis Hamilton's winter job perhaps ?

If that were the case the engine would've blown up spectacularly just before reaching the station.

 

[birchesgreen]

I can just imagine Clarkson aboard shouting "POWER!!!"

 

[Erniescooper]

The Class 175 has button for traction boost in the cab that will load shed the 3 phase supply from the cab and saloon HVAC and also has an input to the engine control module.

 

[D6975]

This reminds me of the days of 31/4s on the Hope Valley route. It didn't take long for drivers to realise the benefit of turning off the EH for a while when climbing.

 

[sw1ller]

175s have an emergency switch which can activate more power in notch 4. In normal conditions, notch 3 & 4 are identical.

Not quite right, I'm just about to pass out on the 175's so you can take this as very well informed information. There is a 6% power difference between notch 3 and 4 and the gearbox changes to the higher gear at a higher speed when in notch 4. So if you stay in notch 3 you will hear the engine note change over at about 58mph, in notch 4 this engine sound will change at about 65mph. (I use the word "about" as none of them are exact!)

In relation to the original question, there is a panel of isolation switches by the front window on the passenger side. (12 round circles, a switch for TPWS isolation and a blue button)

The blue button has a shaded grey box around it linking it with an isolation switch (operated by a drivers key) called Emergency TE Locking.

Put the drivers key in, turn it and hit the blue button and you get TWENTY MINUTES of extra HP amounting to SEVENTY horses! So the guard in this story got his wires crossed. So for 20 minutes you are now getting an extra 70HP and the full 450BHP of the engines.

The systems this isolation switch shuts down are

Saloon HVAC
Cab HVAC
Toilet water heater
Toilet hand dryer
240v sockets

Once the isolation switch has been turned it needs a reset key (which a driver doesn't have) to reset it. After 20 minutes all the isolated systems will restart and you need to hit the blue button again for an extra 20 minutes. Its not very popular in the summer time as passengers tend to bake without Saloon HVAC.

As it states in the post, it was a 2 car, had it been a 3 car they would of just ran with the affected engine isolated and the other two running normally, this wouldn't lose too much time. 175's use a cross feed system so with only 1 engine running, all electrical equipment on any other car works fine.

Hope this clears it up.

 

[eisenach]

Thank you for that very detailed and informed reply. In fact, that makes a lot more sense; I didn't think 20hp in the context of a train would make a great deal of difference.
In fact, it didn't do badly at all. My wife says it left Newport about 10 minutes late and it was only 15 minutes late at Leominster, probably helped by the fact that it was only fairly lightly loaded on the run up the hill to Hereford, where the college students filled it for the portion to Leominster and Ludlow. She didn't notice a lack of heating.