Mixed-Gauge Sleepers on the Tarka Line?

[Trog]

The replacement Neggie rail at Carpenders Park was probably bondless from the mid 1980's into the early 2000's.

 

A lot of the conductor rail on the DC was original and had never been changed since the LNWR installed it. It was really poor stuff originally 105lb weight but with sixty odd years of wear and corrosion, compared with the current standard of 150lb / yard. It was also tack welded up out of short lengths of about 15'-0", after sixty or seventy years in traffic it was only the rust holding it together. You could break it just by looking at it too hard, (Don't try this with 150lb rail as if the wind changes your face will stay that way), you were an idiot if you did any P-Way work that even risked touching it without an arc welder on site.

[Nearholmer]

"The replacement Neggie rail at Carpenders Park was probably bondless from the mid 1980's into the early 2000's."

 

OMFG, is, I think the modern terminology. Thank the good lord, or rather, thank you, that you acted.

 

Your recollection of the state of the CR tallies exactly with mine.

[Trog]

I can not claim any credit as my line of thought was on the lines of, if leaving Carpenders Park un-bonded for so long has not caused any problems. Does that mean you don't need it and will let me take some more away if I ask nicely.

 

We were changing the existing jointed BH to FB CWR at the time, converting one to the other on the straight and fully relaying the tighter curves and through some of the platforms, I also asked if the increase in section and lack of joints in the new traction return rail would balance the loss of the grotty old Neggie rail in the return path. I was just trying to save money and make life easier for the P-Way maintenance and renewals guys who were doing the conversion and relaying work. As the combination of poor access and fiddling with old conductor rails made work on the DC difficult.

[Nearholmer]

"........ not caused any problems. Does that mean you don't need it ........"

 

High resistance can exist in the circuit, and only cause problems in the event of a short circuit. If a short circuit occurs, the high resistance can then cause at least two sorts of very nasty problem indeed, because it can limit the short-circuit current to a level below that which the circuit breakers will "see" as a fault.

 

- if the high resistance is at a single point, a bad joint, a damaged bond etc, there is a possibility that the circuit will "fuse" (burn through, arc, all very nasty, especially in a tunnel) at that point; or,

 

- if the high resistance is effectively "spread", and the conductors are fit to carry the short-circuit current for a long time, whatever it is that is causing the short will itself be the weakest link, and will fuse ........ An old bike frame, or a deliberately placed SCD, will simply get red-hot, then burn through, and arc-away to a load of acrid fumes and little droplets of carbonised metal.

 

So ......... It is quite probable that things went OK between when the scrap rail was supposed to be bonded, and when it was bonded, purely by the grace of god; everyone got lucky.

 

K

[bgman]

For anyone contemplating using the Tarka Line during this coming weekend (1st -2nd Oct ) please not there will be engineering works and a bus replacement service between Exeter St.Davids and Barnstaple coupled with a minor service from Crediton to Exeter as normal.

I expect there will be more "hand-me-downs" used but hey! At least we've got a line that keeps serving the local community.

 

Also, if anyone is feeling thirsty there is a Ciderfest in Yeoford on Saturday at the new village hall ! Hic !