WR(GWR) 3 track Trainshed Draft End Elevation

[cary hill]

For last couple of days I have been attempting to draw an end elevation of the former trainshed at Tavistock South with mixed results (see attachment - sorry it's turned out grottier than I thought it would).

 

I have done the "brickcounting" exercises from photographs and used conveniently placed passengers and station fences to "check" the result.

 

I was reasonably happy with the result at first, but with further cross-checking I decided the roof was sitting too high above rails.

 

I reached this conclusion because the right-hand side roof timber support posts are "integrated" into the platform facade of the station building and sit just above gutter height - "on the roof" as it were.

 

This caused me to measure the height, from ground level to gutter level, of several West Country single storey stations for which I have plans. This exercise suggested that around 50mm (12'6") might be towards the upper end of the range but reasonable for a stone building.

 

Now on 3rd draft. Key measurements at the moment: 240mm (60') - roof span. 52mm (13') - max height of roof. 64mm (16') - rail height to roof base. 50mm (12'6") - platform surface to bottom of roof tranverse support beam or iron -tie rods. roof angle 22.5 degrees approx.

 

There are a few other meassurements on the drawing plus some other assumptions used.

 

The platform may be a little too high?

 

The station building will have more "depth" to it than shown currently, as it was drawn to get a feel for it's height relative to the train shed.

 

The problem is I now feel the overall effect achieved is too "squat" in appearance although I can't see why.

 

It would be a help if anyone out there can see any major "howlers" in the general proportions - so any comments would be welcome, as I need to get the basics right before I wrestle with a CAD program.

 

Thanks, David

[The Stationmaster]

A couple of dumbo questions on the dimensions you have used -

1. What platform height (I can see the number but what was its source?), and - rather critically -

2. What are your track centres based on?

[cary hill]

A couple of dumbo questions on the dimensions you have used -

1. What platform height (I can see the number but what was its source?), and - rather critically -

2. What are your track centres based on?

 

1. The platform height was determined using a piece of Peco platform edging(fool?) but, having since carried out a couple of checks in 3D using a carriage, some track and the edging, I can only think that Peco must assume their underlay is used to increase the relative height of the track, as any alighting passengers appear to need a mini scaling ladder to climb to the platform. 18mm(4'6") must therefore be too high for the platform? I have a note to the effect that 12mm(3') is the maximum height from the rail top surface to the underside of the platform excluding the top surface of the platform, so I assume that I have overdone the total platform height by at least 2/3 mm - 6" or 9" inches?

 

2. I was assuming that my tracks would be 11mm from the platform lower edge to the first rail of the nearest track, 16.5mm track gauge,31.5mm distance between the second rail of the first track and the first rail of the second track and so on, with 50mm separation between track centres .Is that horribly wrong?

 

So I might have gained a few more inches in height for the timber supports. I have also today located a good photograph in my copy of "Western Steam in Colour" which illustrates that the timber roof supports that "sit" on the station roof sit slightly higher than I had originally assumed.

 

I also need to establish if there such a thing as a standard height above rail level for GWR footbridges, although I assume 60mm(15') will be close or is that the minimum permissable clearance? If it is 60mm (15') then this will give another problem because the footbridge at Tavistock South is clearly of a lesser height than the adjacent tranverse lower beam of the trainshed gable end. This might tend to suggest 64mm(16') approx is the distance between the platform surface and the bottom of the roof which doesn't sit well at all with the other assumed measurements.

 

Never mind more work to do and thanks for the interest.

[The Stationmaster]

1. The standard height for platform surfaces in the 1950 'blue book' was 3 ft above rail level (that is measured top of rail level to top of platform surface) and the minimum permitted on new work at that time was 2ft 9ins - so I think your 12mm is a confusion of those two The platforms might be lower of course as many older stations were but if you use the official measurement you can at least say 'boo' to some doubters.

 

2. My reason for asking was that the middle line at Tavistock was siding and should theoretically have had larger than standard 6 foot distances on both sides - but note I do say 'theoretically' - this using standard dimension could have thrown out your calculation of the distance between the platforms. I shall try to fimd some pics to see if they give any clues about spacing.

[Kenton]

16.5mm track gauge,31.5mm distance between the second rail of the first track

Could this be the problem in visual scaling?

you are using an artificial gauge in among all other measurements to 4mm scale

Try making the track in the diagram 4mm scale (ie P4 gauge) the track will then not look so narrow and you may then see the actual distance between tracks. Alternatively see if there is a photo of the track to take track centers from.

At the moment I et the feeling you have a mixture of 4mm:1ft and 3.5mm:1ft scaling.

[Tim V]

Looking at the picture in West Country Branchlines, A colour Portfolio by PW Gray, the roof looks considerably wider, with not such a steep pitch. Have you checked the 25" plans on Old Maps to scale off?

 

I'm with Kenton on this, try putting scale track in the plan.

[Siberian Snooper]

Hi

 

I have sent you some info as a PM which may be of use. It is copyrighted hence the PM.

 

The GW structure gauge specifies that platforms are 3ft above rail level

 

Cheers SS

[cary hill]

Thanks for all the replies,advice and observations.

 

My "crimesheet" would appear to include all of the following:

 

1. Hopelessly high platforms.

 

2. Hybrid scaling - causing the trackbed to be far too "narrow" which contributes to :

 

3. The relationship between the width and pitch angle of the roof looking suspect.

 

4. A general lack of attention to detail e.g. it is blatently obvious from closer study of photographs that the "Middle Siding" track is much closer to the Station Building track than the other track because there is point rodding between the "Middle Siding" and other track.

 

Following on from the above I have looked at the pitch of other trainshed roofs for which I have plans.

These suggest that a 5:4 ratio between the timber supports(platform to roof lower edge) and roof lower edge to roof apex is common, so my approx 1:1 ratio looks "wrong".

 

I have revisited the OS old maps of Tavistock South and 40' to the inch plan I have. These both scale the "width" at around 60' or possibly slightly more and suggest that my platform widths are out as well.

 

I feel I need to "fix" the horizontal elements i.e.platform plus track widths with some degree of confidence and at least two of the vertical elements to progress properly, as the present the relationship between the different elements is distorted by cumulative errors.

[Neal Ball]

Hi David,

 

Sounds like a great project, good luck!

 

Have you seen this?: http://www.collectingbids.com/auction_details.php?name=TAVISTOCK-SOUTH-STATION--PandP-Disc&auction_id=108865

 

I realise it's out of date as far as the auction is concerned, but the 'photo might be of interest.

 

Regards,

[cary hill]

Hi David,

 

Sounds like a great project, good luck!

 

Have you seen this?: http://www.collectin...ction_id=108865

 

I realise it's out of date as far as the auction is concerned, but the 'photo might be of interest.

 

Regards,

 

Thanks for pointing that 'photo out. Fortunately I have already managed to "capture" a bigger version of it. It is one of my more useful "head-on" 'photos and makes a change from the plethora of "three-quarter" views of assorted Prairies/Panniers plus stock that I have.

 

Thanks for the "good luck" wish as well, as I may need it because, for supposedly one of the most photographed Devon branchline stations, a lot of it seems remarkably camera-shy.

[R A Watson]

An old friend of mine, Bernard Mills, published a book on the Plymouth, Tavistock and Launceston line called Surprisingly "The Branch" in support of the, then, embryonic Plym Valley Railway.

 

This contains several of his own pictures of Tavy South where he used to work on station relief duties. I have found this link to amazon where copies are available http://www.amazon.co.uk/Bernard-Mills/e/B001KHDZ9U

 

You may find this helpfull.

[Neal Ball]

 

...................Thanks for the "good luck" wish as well, as I may need it because, for supposedly one of the most photographed Devon branchline stations, a lot of it seems remarkably camera-shy.

 

Strange you say that, I have 4 shelves of Railway books and have nothing on Tavistock.

 

Have you tried Transport Treasury?

 

Regards,