Class 85 Smoothing Choke modification dates?

[ClikC]

Hi guys.

 

Bit of a wild one this, but exactly as the subject says, does anyone have any info reguarding the dates the modifications to the smoothing chokes on the Class 85's took place?

 

My period is may 1974. Inevertably (the VERY rare) photos of the class during that period are of the 'A' Side of the loco.

 

Pointers welcome as too where too look very welcome, also I suppose any relivant info on the mods themselves, and the simular mods that took place on the Class 81's also welcome.

 

Regards

 

Matt / ClikC

[giz]

The Brian Webb and John Duncan book on AC locos says that the chokes were modified after the originals started overheating once the locos were used over Shap and Beattock. It also says that the electronic temperature sensing on the new chokes caused some problems during the hot summer of '76 so that obviously dates them prior to that but there doesn't seem to be any further information.

[ClikC]

The Brian Webb and John Duncan book on AC locos says that the chokes were modified after the originals started overheating once the locos were used over Shap and Beattock. It also says that the electronic temperature sensing on the new chokes caused some problems during the hot summer of '76 so that obviously dates them prior to that but there doesn't seem to be any further information.

 

Thanks for the info Giz, seems like i'll have to just go with photo's ref's.

 

Regards

 

Matt / ClikC