Handbrakes on DMUs

[Ken H]

The other week I caught a train from Bingley to Leeds. It was a 158. At leeds it went to an empty low numbered bay. As we got off (it was very full) the engines stopped, i assume by the driver.

We know that air braked trains can slowly lose braking power when the compressors are not working, so:-
Will the driver have applied the handbrake in the cab he had been driving in?
If he did, how would the next driver know to release it? Would he have to start the engines and get brake pressure up before releasing the handbrake? So some duries to perform in the rear cab before he can go to the front cab?
Are the low numbered platforms at leeds level? Are there different regs for sloping platforms?

 

[Tynwald]

158 have automatic parkbrakes. As do pretty well all trains now. Only old heritage trains like class 37/47 do not have them.

 

[driver9000]

No. The parking brake applies automatically as the main air pressure drops. The main air holds the spring off so it's a fail safe device.

 

[Intercity Exec]

The loss of air pressure you allude to releases a spring that applies the brakes. As such, air pressure is what is preventing said spring from applying them. In reverse, on restarting the engines the raising air pressure will ease off the spring and at the same time be supplying the brake cylinders. That is why upon restarting the engines if main and brake air is particularly low it is prudent to ensure brake cylinder pressure is climbing to ensure the parking brake isn’t “blown off” (yes, I know!) prior to sufficient air holding the service brake on.

In terms of the engines on a 158, normally it would be expected that they would continue running even once shut down as the air conditioning is run down. The fact this didn’t happen in this case means the air con either wasn’t running or the driver bypassed the shut down delay for whatever reason.

Regs are no different whether level gradient or not, a train is simply not left without a parking brake applied or if a method for this to occur automatically isn’t in place.

 

[Ken H]

Didnt know about the automatic parking brake. Thanks.

 

[Efini92]

In terms of the engines on a 158, normally it would be expected that they would continue running even once shut down as the air conditioning is run down. The fact this didn’t happen in this case means the air con either wasn’t running or the driver bypassed the shut down delay for whatever reason.

Leeds drivers always do that, it’s no wonder the air con never works on the northern 158’s.

 

[dk1]

Parking brake needed to be applied on 153s but thankfully anything to do with those dreaded units are long done for me now.

 

[driver9000]

Parking brake needed to be applied on 153s but thankfully anything to do with those dreaded units are long done for me now.

Never had to apply the parking brake when I signed 153s as they had been modified by the time I learned them. I know the parking had to be applied once over to prevent them wandering off on their own though.

 

[dk1]

Never had to apply the parking brake when I signed 153s as they had been modified by the time I learned them. I know the parking had to be applied once over to prevent them wandering off on their own though.

Always had to on our fleet if left for any length of time. PA handset would be wound round the brake controller as a reminder.

 

[Ashley Hill]

Parking brake needed to be applied on 153s but thankfully anything to do with those dreaded units are long done for me now.

Yes, I remember many cab/cab calls from drivers following a very slow departure asking to release them. As mentioned above they were later modified.

 

[driverd]

Leeds drivers always do that, it’s no wonder the air con never works on the northern 158’s.

Doesn't affect the air con (other than allowing the carriage to warm a smidge) saves fuel and prevents filling everyones lungs with particulates. Its also policy at northern as far as I'm aware.

What's not to like?

 

[skyhigh]

Doesn't affect the air con

It doesn't allow the system to pump down and knackers the air con system.

Its also policy at northern as far as I'm aware.

It's not! You're meant to let it shut down when it's ready, not kill it immediately.

 

[Efini92]

Doesn't affect the air con (other than allowing the carriage to warm a smidge) saves fuel and prevents filling everyones lungs with particulates. Its also policy at northern as far as I'm aware.

What's not to like?

Of course it affects the air con. By forcing the engines off stops the aircon going into its run down phase which damages the condensers and stops them from being able to vent properly when the carriages get to warm.

 

[wobman]

Doesn't affect the air con (other than allowing the carriage to warm a smidge) saves fuel and prevents filling everyones lungs with particulates. Its also policy at northern as far as I'm aware.

What's not to like?

Tfw shut the 158s down immediately at Birmingham International, the company policy is to shut them down once the service has arrived due to pollution.
On the 158s at tfw they shut the engines down straight after pressing the button and there's no policy regarding air con.

 

[Efini92]

Tfw shut the 158s down immediately at Birmingham International, the company policy is to shut them down once the service has arrived due to pollution.
On the 158s at tfw they shut the engines down straight after pressing the button and there's no policy regarding air con.

That’s probably why they are always running round with the hopper windows open.

 

[158747]

It is possible to shut 158 engines down without damaging the air con. Just press engine stop button briefly, the air con will then shut itself down, the engines stopping a minute or two later, once the air con has shut down.

 

[driverd]

It is possible to shut 158 engines down without damaging the air con. Just press engine stop button briefly, the air con will then shut itself down, the engines stopping a minute or two later, once the air con has shut down.

Precisely, not entirely sure what Efini92 is on about and they haven't replied directly yet.

I'm just curious if they know something we all don't!

 

[TurboMan]

Precisely, not entirely sure what Efini92 is on about and they haven't replied directly yet.

I'm just curious if they know something we all don't!

I assume it's because a long press on the engine stop button acts as an emergency engine stop which shuts the engines down immediately and doesn't allow the aircon to go through its shutdown cycle.

 

[driverd]

I assume it's because a long press on the engine stop button acts as an emergency engine stop which shuts the engines down immediately and doesn't allow the aircon to go through its shutdown cycle.

I thought the implications was turning the engines off in any fashion (ie: properly or not), damages the aircon?

 

[tomuk]

On 158s, as built, due to the time needed for the air con to pump down there was a delay added to the engine stop circuit. If the button is pressed normally the engines would shutdown automatically after a couple of minutes delay. If the button is held in the engines shutdown immediately, this is not optimal for the aircon. The aircon system n the 158s has always been marginal as it was specced with a low capacity to keep the weight down. This is not helped by the need to run the wrong more environmentally friendly refrigerant, the long refrigerant pipes leading to leaks and the mis-operation of the system by staff, engine stop, control panel messing and window opening.

 

[Efini92]

Precisely, not entirely sure what Efini92 is on about and they haven't replied directly yet.

I'm just curious if they know something we all don't!

Its been answered since by tomuk.