Signals to driver when train starts off

[tsr]

On the SR slammers, 2 on the bell was often acknowledged by 2 on the Loudaphone buzzer. Not sure if this was an informal arrangement though.

I believe this was done when either the bell was defective at the driver's end, or the design meant they could not use a bell to give an acknowledgement of the guard's signal. I can only go by what I am told as I have never despatched a slam door unit. Somebody will no doubt correct me ASAP if I am wrong.

Southern 455s still feature a design such that the driver cannot reply to a conductor giving any signal on the bell (where conductors still work these services). In theory a signal could be returned using the call tone on the cab-to-cab phone, but I've never heard that done, and of course it would be both fairly quiet and ambiguous as to meaning. There are also a number of other "interesting" features, such as having to check the desk interlock light on many occasions because the door panel lights have failed safe on quite a few units, and the fact that unlike the SWT units, these do not have guard operating panels in the passenger vestibules.

 

[cjmillsnun]

I always think that the two beeps repeated back by the driver on units such a sprinters is a bit of an anachronism these days. It's like a carry over from steam days when the driver would sound the whistle to acknowledge the green flag.

I sometimes wonder if it's to tell the guard "Yes, it's me driving, I havn't been kidnapped and the train isn't being driven by aliens who don't know the code"!

The Herald of Free Enterprise capsized because assumptions were made. Had positive reporting been initiated (i.e. the Master ringing down to the car deck "Are the bow doors shut", and the assistant bosun answering "Yes, they're shut"), it never would've happened. Instead the master only expected notifications if there was a problem... Well there was a problem, the assistant Bosun was asleep in his cabin...

Whilst not quite the same, the two bells back indicates that the driver is alert and concentrating. It's a reassurance to the guard, and as others have mentioned, allows a stop if there was a misread of the bells.
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On the SR slammers, 2 on the bell was often acknowledged by 2 on the Loudaphone buzzer. Not sure if this was an informal arrangement though.

Pretty sure it was a formal arrangement, as the guard would have to be in a guard's compartment to send the two bells. Therefore would always be in a position to receive the acknowledgement.