Signal boxes on gantries - construction materials

[John Webb]

In the past few months several model railway layouts in Railway Modeller and the Hornby Magazine have had gantry-mounted signal boxes. A few of these seem to have been existing models with brick bases simply plonked down onto a girder gantry above the tracks.

Now none of my books on the prototype or on modelling signal boxes shows a brick-based box on a gantry - they are always wood, whether of one or two floors. And to be honest I can't imagine the railways erecting a brick-based box on a gantry because of the much greater weight of the bricks compared to wood needing a much stronger structure!

So were there any examples of brick based boxes on gantries in real life?

[Stuart Johnson]

In a field where it's unwise to be dogmatic, because there is always an oddity somewhere, I think this has to be one situation where the only correct answer is no. You've already worked out why!

[Mike Hodgson]

The easiest way to build model gantry box is to take a signalbox kit and shove it on top of a gantry - modellers may count the rivets on a loco but when it comes to signalling it's only "scenery". I'm not saying that modellers aren't trying, but they generally know very little about signalling, and even if they want to model an actual box, the problem is that it was probably demolished decades ago, and even though some photos may exist, the box itself would have been off limits to the general public. Magazines also tend to perpetuate any inaccuracies.

[JRB]

Brick on gantry is not out of the question. There have bee several booking offices done that way next to road bridges - Paddington B.R. for example.

[John Hinson]

So were there any examples of brick based boxes on gantries in real life?

There certainly were, but I can't think of any outside London Transport lines.

John

[MRFS]

I can think of several overseas - and JH beat me to it with the LPTB suggestion.

[John Webb]

Re the LTPB - I take it these were relatively small single storey buildings?

I take the point about booking halls - but then I assume that the adjacent bridge helped to support the more substantial girder-work that was needed.

[MRFS]

Not really. Search for pictures of the 1946 box at Aldgate. There wasn't much difference between a brick gantry box and an ordinary box, apart from the roof concrete may have been slightly thinner.

[Frank]

Hello,


take a look at:

www.reiterstellwerk.de

But they where built from what where here called Viertel-Stein (1/4 Brick) because to reduce the weight.

[JRB]

Re the LTPB - I take it these were relatively small single storey buildings?

I take the point about booking halls - but then I assume that the adjacent bridge helped to support the more substantial girder-work that was needed.

Bishop's Road booking hall was independent of the bridge. The gantry remained after the bridge went. I don't think the county council or whetever wold welcome a sighnal box or b.o. hanging on their bridge.

[Pete2320]

So were there any examples of brick based boxes on gantries in real life?

There certainly were, but I can't think of any outside London Transport lines.

John

Some non LT ones that spring to mind are Brighton, Manchester Central and Glasgow St Enoch. Curiously, like the LT boxes, all contained power frames.
I'm sure we have discussed this before but I can't find it. I don't think it was in it's own thread.
However John Webbs' question refers to brick based boxes on a gantry, implicitly with a wooden upper floor. I certainly can't think of any of these.

Pete

[John Webb]

Some non LT ones that spring to mind are Brighton, Manchester Central and Glasgow St Enoch. Curiously, like the LT boxes, all contained power frames.
I'm sure we have discussed this before but I can't find it. I don't think it was in it's own thread.
However John Webbs' question refers to brick based boxes on a gantry, implicitly with a wooden upper floor. I certainly can't think of any of these.

Pete

Pete - yes, you are correct - I should perhaps have made clear that the examples I've seen on models and which I was questioning were all wooden first floor construction on a brick ground floor base.

There are quite a lot of kits of all timber boxes available, so modellers should be able to get reasonable accuracy!?

[S&TEngineer]

Well as MRFS has mentioned above here is the Aldgate example: http://www.ltmcollection.org/images/web ... 000uus.jpg

[Andrew Waugh]

So were there any examples of brick based boxes on gantries in real life?

There certainly were, but I can't think of any outside London Transport lines.

Some non LT ones that spring to mind are Brighton, Manchester Central and Glasgow St Enoch. Curiously, like the LT boxes, all contained power frames.

Not so curious...

Fire was considered to be a major risk with early power frames. Insulation was not as developed as it later became, and was easily damaged. Further, where points were electrically operated the early designs had the full operating current passing through contactors on the frame and thence to the points. And we shouldn't forget the power supply aspects... which could include internal combustion engines to drive generators, large banks of batteries for operation during power failures, and "high" voltage power with step down transformers.

Brick, concrete, and steel construction was considered to be 'fire proof', or at least more fire proof than construction using wooden signalboxes.