Great Western Two Tone Whistles Enquiry...

A former GWR worker told me that footplate crews used to be fined if they played around with the two noted whistles which is interesting.

 

Probably more akin to a harmonica where the pitch is largely determined by the vibrations of a metal reed. In a loco whistle the reed is a flat disc & there's a very narrow gap between its edge & the whistle casing. The width of the gap, the amount of spring in the disc determine the pitch, nut that can also be affected by the steam pressure. I guess that's why the whistle note slides up to pitch very quickly - there's a brief period between the valve being opened & full pressure being applied that causes the 'whoop'.

The terms 'Fourth' & 'Fifth' relate to scale intervals... F'rinstance, the C Major scale is comprised of the notes
C D E F G A B (C) so C=1 (or Root), D=2, E=3 etc., up to (C)=8 (or 1 but an octave up). So the Fifth of Cmaj is G, & the Fourth is F. Intervals are usually expressed in roman numerals, so I-IV-V gives the formula that's kept Status Quo in beer money for half a century .

In the case of the GW whistle, if we assume the brake note (D#) to be I, then the alarm note (G#) is IV, i.e. a Fourth. BUT... If we assume that the alarm note is I, that makes the brake note a V, but as it's pitched below the root, it becomes an Inverted Fifth.

D#Maj = D#, F, G, G#, A#, C, D, (D#)
G#Maj = G#, A#, C, C#, D#, F, G, (G#).

The roman system is usually called 'Nashville Numbers' & is a fantastic shorthand way of communicating a generic tune's structure if you're busking it. If a guitarist tells me "Shuffle in E, Quick IV, II-V Turnaround" that's pretty much all the info I need to bolt a workable bass line onto something like this:



Pete S.

 

But you only go so far with two notes.
I wonder if a number of locos could be lined up each with their whistles tuned to a different note.
If well conducted, they could perform an interesting rendition of simple songs such as the Blue Danube waltz..........

 

I remember something of that ilk at the Talyllyn Railway a while back.

 

It was reported in "Trains Illustrated", IIRC in 1959, that 5020 "Trematon Castle" had been fitted with a chime whistle. As the loco was shedded at Canton at the time, I presume some "60097" fitter had borrowed it from an 88A Britannia!

 

I think you've described an air horn there. Whistles are more like organ pipes, it's the length of the chamber beyond the disc that matters, and thus the resonant frequency of that chamber. That is why the GWR brake whistle is longer than the service whistle (or LMS hooters are longer than LNER dog whistles). The resonant frequency is pressure dependent, so you still get that slide up to pitch.

 

Makes sense - if the lower-pitched whistle is an explicit instruction for the guard to carry out a specific action (i.e. apply the brake), any misuse could be misinterpreted and possibly lead to an accident. After all, you wouldn't expect a guard or shunter to start flashing coloured lights about, just because they wanted a bit of a light show, would you!

Tom

 

Thanks for that Pete. I've been playing the blues guitar since about 1960 (of course not quite to the level reached by the brilliant Rory G!) but never knew any of this! Thas for the YouTube link too. Can never have enough of RG.

Steve

 

Ahhh... that makes more sense. In my defence m'lud I normally associate the term 'organ' with a 1/4 ton of motorised valvey goodness whacked through an overdriven Leslie

That really surprises me! I thought that the Nashville interval system was universal amongst musicians since it cuts out a shedload of unnecessary verbiage; it certainly gets bandied about a lot at a couple of blues jams I go to up here. A while ago I compiled a list of 'Blues Terminology' that's also been a great help - PM me if you want a copy.

P.

 

The legendary LBSC (miniature loco designer) used to publish designs for Christmas presents eons ago in the Model Engineer-I saw his steam powered nutcracker in a back issue once, and he had a design for a steam calliope that I started building ten years ago... Lots of fun, pot boiler and 12 tuned whistles for playing songs. Think it might empty the boiler pretty quickly if you play too many chords though! Wonder if anybody ever made one?


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Not the LBSC version, but one available on evilBay at the moment:

http://www.ebay.co.uk/itm/111561334460

 

Wow, looks pretty bonkers!


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If anyone wants to see GWR two-tone being abused for the sake of it (or just wants an excuse to watch the film again) The Titfield Thunderbolt is still on BBC iPlayer for another couple of days I think.... Very effective two fingers up to one of Mr Bulleid's finest in the opening scene!