I thought I'd start a thread for those nagging random questions that sometimes plague us.

I'll start with "Why is the bit in the middle of a point called a frog?"

Why do some bridges etc. have rails inside the main rails that appear to have no function?

Quote from: petercharlesfagg on November 12, 2013, 10:58:34 PM
Why do some bridges etc. have rails inside the main rails that appear to have no function?

http://en.wikipedia.org/wiki/Guard_rails_(railroad)

Quote from: captainelectra on November 12, 2013, 10:29:51 PM
I thought I'd start a thread for those nagging random questions that sometimes plague us.

I'll start with "Why is the bit in the middle of a point called a frog?"

Frog - The part of a railway switch or turnout where the running-rails cross (from the resemblance to the frog in a horse’s hoof) ......

http://www.horsemanmagazine.com/wp-content/uploads/2008/09/horse-hoof-frog.jpg

Quote from: griffo49 on November 12, 2013, 11:05:43 PM

Quote from: petercharlesfagg on November 12, 2013, 10:58:34 PM
Why do some bridges etc. have rails inside the main rails that appear to have no function?

http://en.wikipedia.org/wiki/Guard_rails_(railroad)

That picture almost proves my point, in a stretch of track with no apparent need?  Peter.

Quote from: petercharlesfagg on November 12, 2013, 11:18:06 PM
That picture almost proves my point, in a stretch of track with no apparent need?  Peter.

The need arises once the accident has started to happen! The function is that the outside of the guard rail contacts the inside of the flange, the reverse of normal running.

Guard rails are normally fitted on bridges with no solid parapets, to provide some extra restraint to make it less likely that the train will go off the edge if it derails for any reason.

Check rails are slightly different, being much closer to the running rails they contact the back of the wheel near its normal running position and therefore prevent a derailment happening in the first place.  Used in switches and crossings and on tight curves. 

Quote from: griffo49 on November 12, 2013, 11:21:11 PM

Quote from: petercharlesfagg on November 12, 2013, 11:18:06 PM
That picture almost proves my point, in a stretch of track with no apparent need?  Peter.

The need arises once the accident has started to happen! The function is that the outside of the guard rail contacts the inside of the flange, the reverse of normal running.

Thankyou, no-one had mentioned the possibility of accidents before but now I understand better!  Peter.

OK, Another thing I've often thought about.

Why with the old semaphore signals did they not standardise instead of having upper and lower quadrant indicators?

Peter.

Quote from: griffo49 on November 12, 2013, 11:09:00 PM

Frog - The part of a railway switch or turnout where the running-rails cross (from the resemblance to the frog in a horse’s hoof) ......

Next nagging question - why do horses tread on frogs? Can't they see where they're going?

Peter:

In regards to your checkrails on bridges thread, try driving around New Zealand (especially on the West coast of the South Island). You drive onto a ONE lane bridge (usually wooden), with a railway line also running through the middle of it! So effectively you could be stuck with a freight train heading straight toward you! Actually it could even be the Tranz Alpine Express if you happen to be near Greymouth!

I kid you not! I'm sure some of our NZ members will back this up!

George.

PS: I love NZ, I really do. Heading back for a couple of weeks after Christmas. 

Last post: Good one, Mick. There go another couple of ribs from laughin' too much.

Quote from: petercharlesfagg on November 13, 2013, 08:53:50 AM
Why with the old semaphore signals did they not standardise instead of having upper and lower quadrant indicators?

Peter.

Within any one (pregrouping) railway they were usually standardised one way or the other...

Why some standardised on upper and others lower, is mostly due to the preferences of whichever outside supplier was used, and of course the Great Western's tendancy to be b******* awkward and do things differently to everyone else...

No....The GWR way was the correct one of course !

OK, OK .....Sorry..........I'm running for cover !!

Quote from: port perran on November 13, 2013, 03:59:01 PM
No....The GWR way was the correct one of course !

OK, OK .....Sorry..........I'm running for cover !!

Stand firm on your conviction I'm right behind you! Oh and don't run before you tell me because you might knock me over. 

Even into grouping days there were lower quadrant signals on the LNER but they gradually got phased out.