Track A1 "Train Sequence" is almost certainly a Joe Meek recording, I have a copy of Joe Meek's train recording and it sounds the same. and ..
Track A10 "Ceremony Of The Keys" is identical to the 'mono' recording I have from Joe Meek, although he titled it "Order Of The Keys". I put Meek's recording onto Youtube a while back at https://youtu.be/nV0pBPlhoKQ
Both these tracks on the album are not credited.
Joe Meek used a portable mono tape recorder getting these sounds, so it's possible Decca has converted these to 'pseudo-stereo' for this album.
The other thing I've learned since entering this, which may help with dates, is that although the unboxed Decca logo labels on SKL / SXL s may look the same at first glance, the text in the upper left portion of the label, which reads: "Original Recording By..." and which signifies the earlier pressings, was replaced by: "Made In England by...".
(not sure of the exact date of this change though).
((And also the presence of the "Deep Groove" in the label says it's early sixties))
As your sleeve has the flips on the back still, this would seem to place it before 1964-ish (by virtue of looking at The Rolling Stones debut album, which only briefly sported flip-backs, and other Deccas of this kind of genre)...
And Decca seem to have done away with the flip-backs quite early compared to other labels... they kept pretty much the same sleeve construction throughout the sixties and seventies, which is why it can be difficult to date them based on this element - you've got to go to the labels really.
As far as to how long this remained in catalogue --- my copy may add some insight. While I don't know the exact year of my pressing the matrix numbers and other dead wax stampings may yield some clues. The exact matrix numbers are a: ZAL-3941-6E and b: ZAL-3942-8E. If I understand things correctly, the 6 and 8 indicate a later lacquer and the E means Stan Goodall created the master lacquer. The A side It also has a 'UU' stencil, so using the BUCKINGHAM code it is 22nd stamper made from the mother. There is also a 1 on indicating that it was the first mother. The B side has a 'UA' indicating that it is the 29th stamper made from the mother. There is also a 1 on indicating that it, too, was the first mother.
Added a somewhat hacked up scan of an un-scalloped laminated sleeve. Also added label variation with a K/T tax indicator and, on the A side, indication that BIEM seem to apply only to cuts a and b, and not BIEM logo on B side.
I didn't know what this was when I found it, I was just suitably intrigued by the evocative title and groovy cover.
I actually took it for quite a - relatively - recent album, as the cover has something strangely modern looking about it... as compared with more cotemporary albums to this; Like a modern retro design or something, if you get my drift.
But it is actually one of those items of interest to fairly broad range of collectors from different spheres of interest: Its' a "sound effects" record, it's an early stereo record (establishing some of the key features of Decca's label design for stereo albums), and by virtue of that, it also features a couple of classical performance excerpts lifted from other complete early Decca stereo issues, and which would now set you back a fair few bob to get in their entirety.
... as well as what must be a pretty unique rehearsal session of one such classical artist: Conductor Ernest Ansermet.
Features to note that I've been foraging in the internet undergrowth for are that this was in constant press in those early years of the introduction of stereo, and so appears in a variety of sleeves and represses, although the label always seems to be (At first glance at least) unchanged... That is that I haven't yet found a "Boxed" Decca logo label, or indeed even a "Narrow Band" label (They may well be out there).
But firstly the sleeve back is the key feature of change, beginning with this laminated flip-back design, with intermittent grey shaded border (I think this is what is referred to in some listings I've seen as the "Greyback" element (I think the "Blueback" reference is the label, which is, well, blue in this case, but is black on Decca SXL series labels), and the red text heading and underscore of that section.
This was followed by a straight edged flip-back sleeve (Un-scalloped), and then the flip-backs disappear altogether, and a variety of plain black texts with no red or border.
The front of the sleeve does not seem to change at all, except one or two I've seen that have a yellow relief on the "Stereo Sound" words (As with the Canadian issue linked below), and one later repress which has a richer, "Orange-ier" sepia tone to the image.
As regards the labels, the early Decca labels have: "Original Recording By" in the upper left section, above the silver band (This was later replaced by different text), and have a deep groove in the label (This too disappears on later labels)... But the one feature of change here that is easier to spot is the rights box: The "BIEM" box seems to have been moved in a couple of cases.
Also, these copies, like the EPs f the time, are dated on the bottom right of the sleeve on the flip-back.
A good copy of the first (ED 1) can currently go for upwards of £50 (Provided they're not as tatty as mine!).
((Look out for any classical Deccas bearing that triangular "Sterophonic" logo on the front cover, that you see on the bottom right of the rear of the sleeve on this... these are the very earliest stereo Decca classics.... and are always checking the value of online :)))