Hornby Sentinel - including cranked version

[Ruston]

According to Adrian Booth's 'Industrial Diesels' (Bradford Barton) the wheelbase should be 6'6". The rod coupled version had a wheelbase of 6'0". Of course individual locos could possibly differ.

The same figures are shown in my 1964 Sentinel brochure.

[Boscarne]

That's a useful and reassuring update from Simon Kohler, many thanks for that. (Can't see the flywheel either though....)

 

Loads of prototype inspiration to be found here;  http://www.flickr.com/groups/1814638@N20/pool/

 

It would appear that the side sheets were quite often removed when air brakes were fitted, the compressor etc went in a box alongside the bonnet although patterns varied, choose your prototype carefully..

 

 

Incidentally there were scale 4mm drawings of a 4w chain drive and 6w rod drive Sentinel in Railway Modeller June 1968.

[Michael Edge]

Wheelbase dimension of chain drive locos is nominal, it will increase as the axleboxes are adjusted to take up wear in the chains. This is what the rods and turnbuckles are for.

[Adam]

Since we have an elevation drawing of the actual model and the dimensions of the real thin, I've indulged in some attempts at scaling (in the old fashioned method of printing it out and attempting to scale from an independent known dimension - in this case, the centreline of the buffers to the railhead which on the prototype should be c. 3' 6" or, in 4mm scale, 14mm.

 

Since it isn't immediately obvious whether the CAD shows the base of the flange or the tread (I think it's the former, but I'm not sure) there's a degree of variation here, but a bit of basic maths suggests that the mech' has a wheelbase which scales out between 5' 3" or 5' 6" (22-23mm). Hmm.

 

Adam

[Boscarne]

Been doing a bit of measuring too, scaling the CAD against a scale drawing. Assuming Hornby have the length over bufferbeams right (??) that puts the model's wheelbase at 24mm. It should nominally be 26mm. The 'front' axle is in the right place, but the one under the cab is wrong. Also the ride height seems a little high...

[brushman47544]

Well those facebook shots have killed my enthusiasm stone dead - I hadn't really thought about it before, but having the side sheet split with the  chassis passing between it has rather spoilt the effect - particularly on the Esso livery where the chassis is painted black, and I don' see a way or re-working it without making the mechanism impossible to get at and requiring a total repaint.

 

Jon

 

The side sheet split is an issue - not that it would be an easy thing to mould parts of the cab integrally with it; there would have to be a join somewhere - but quite a number of Sentinels, especially in later years, lost the sidesheets altogether or had handrails substituted in their place. I imagine that this was because getting in to maintain them was a bit of a pig to do.

 

I have an idea how to hide the join in the chassis side sheet: a sheet bass overlay - I have one left over from my Judith Edge version since they were a different shape on the rod-drive variety. That's getting into full repaint territory too but that's something I would probably want to do in any event. A similar solution might apply for the side sheets.

 

If I'm honest, I wouldn't be considering this at all - price permitting - were it not for the spare Judith Edge parts I have in the bits box!

 

Adam

 

Why so negative? It's doesn't look that bad surely. Why not give Hornby the benefit of the doubt - my guess is that Hornby has designed the loco with the side sheets in two parts deliberately, so later on they can model the version with handrails without major tooling changes.

Edited February 12, 2013 by brushman47544

[Adam]

Andrew, I see what you're saying, and its an old saw in these sorts of threads, but 'benefit of the doubt' over what? Brian merely said he preferred how the loco' looks that way: that isn't negativity, it's a personal preference and, since it's a separate part, something which is easy to do if a modeller so wishes. EDIT: this refers to a quote originally included by 'Brushman47544' and since edited away (apologies for any confusion this causes)

 

I already have a model of a Sentinel diesel from the Judith Edge kit, and I don't really need another but if I were to buy one, the two would have to run next to each other and be to a comparable standard so that's my starting point.

 

The Hornby model - as it stands and yes, it may change - has two errors of detail: the size of the axlebox covers and (apparently) the wheelbase, though the one emphasises the other. I doubt that the mech' will be altered at this stage because that's fundamental to the design but the axlebox covers might. I hope so.

 

The other features are production compromises but to a greater or lesser extent, compromises which badly affect the appearance of the finished model (in my view). The footplate sidesheets are fair enough: it would be an utter swine to mould any other way and look far from terrible if assembled correctly - there is a join there on the real thing but it's welded up. Modelling the handrails might be an option for later Hornby releases, who knows? 

 

The chassis skirts would require modification for me (but apparently not only me) to be happy with it especially if they were delivered with the black outline (I don't think they will for what it's worth), but the join line will spoil the look of the model. The clean lines are characteristic of the prototype and the join is very obvious because it isn't there on the real thing and - unless painted flat black - will show up. My desire to repaint the model is simply because I have a prototype in mind. 

 

Adam

Edited February 12, 2013 by Adam

[jonhall]

Why so negative? It's doesn't look that bad surely. Why not give Hornby the benefit of the doubt - my guess is that Hornby has designed the loco with the side sheets in two parts deliberately, so later on they can model the version with handrails without major tooling changes.

 

The Esso Sentinal always was going to be an impulse buy for me, and if you have dragged through however many pages of the original Hornby announcement page you will already have seen these photos

 

 

 

 

I don't 'need' one at all, let a lone a kit one and an RTR - the only reason I have was because the preserved one looked so smart when I first saw it (alas its been left out in the sun and faded just as badly as my dads pink (formally red) car).

 

If the livery applied by Hornby is 'correct' and the metal chassis is painted red across the side skirts and if the joins between parts is tight, then they might just carry it off, but thats not what the photo's shared on Facebook imply,

 

Jon

Edited February 12, 2013 by jonhall

[Boscarne]

A little bit of digging led me to this article on the Rolls Royce Sentinels from a 1968 Council of Industrial Design magazine;

 

http://vads.ac.uk/diad/article.php?title=233&year=1968&article=d.233.43

 

 

Clive.

Edited February 12, 2013 by Boscarne

[Pandora]

Excuse my ignorance,  the chain drive sentinels,  is it true they were originally steam shunters,  vertical boilers  etc,  that were taken back t Sentinel for updating, conversion to diesel using the original frames but with new cabs / sides/  buffer beams etc etc?

 

In the drop dead gorgeous stakes, how about the 1934  Sentinel S4/ S6/ S8 steam lorries?  four cylinder engines, shaft drive to the rear wheels, and the boiler behind the driver and mate 

Edited February 12, 2013 by Pandora

[Adam]

Excuse my ignorance,  the chain drive Sentinels,  is it true they were originally steam shunters,  vertical boilers  etc,  that were taken back t Sentinel for updating, conversion to diesel using the original frames but with new cabs / sides/  buffer beams, etc.?

 

Most were not - though Sentinel did good business in the '30s converting other companies' conventional locomotives to vertical-boilered machines using standard Sentinel parts. Some steam Sentinels were converted in the way you describe in the '60s, but most of these were done by Thomas Hill of Rotherham, a Sentinel agent. The design of the chassis was fundamentally similar.

 

Adam

[brushman47544]

[snip]

 

[snip]

 

Just to be clear, my earlier post was referring to the split side sheets only, not to any other possible errors with the model, although I appreciate from comments throughout this thread that that may be a minor concern compared to other issues such as those axlebox covers.

[bigherb]

The footplate sidesheets are fair enough: it would be an utter swine to mould any other way and look far from terrible if assembled correctly - there is a join there on the real thing but it's welded up.

 

Adam

There should be a join, the side sheets are detachable bolted to the cab front.

[Butler Henderson]

The join between the side sheet and the cab can be seen in this photo, note the stagger in lining

 

http://vads.ac.uk/diad/bres/pub/COID/233/046.jpg

Edited February 13, 2013 by Butler Henderson

[jonhall]

There should be a join, the side sheets are detachable bolted to the cab front.

 

I think that varies loco to loco - on many - including the Cattewater Esso example the side sheet is welded and someone has spent a great deal of time with filler smoothing it off, there is some evidence of a horizintal seam at the footplate level these days where rust has got into the gap and opened it.

 

The join between the side sheet and the cab can be seen in this photo, note the stagger in lining

 

http://vads.ac.uk/diad/bres/pub/COID/233/046.jpg

 

No matter how hard I look at that photo I can't see where you see the split, but there is no doubt in my mind its there (on SOME locos) I am starting to believe that some of the rod drive examples have a slightly narrower body than chassis. In my next couple of posts I'll look at a few examples of each.

 

Jon

Edited February 13, 2013 by jonhall

[jonhall]

SO the first 3 photos are all of the same loco, undergoing an engine change at Long Marston

 

As you can see, there is a very distinct horizintal split at the footplate level with the cab narrower than the chassis, and the side sheet above foot plate is clearly bolted on (from the inside view) but someone has gone to a great deal of trouble to smooth the join outside.

 

 

Next is one of Wabtecs, here there is clearly some extra bracing rivited to the inside of the upper top sheet, but the vertical join between upper top sheet and can is smooth, and the cab/topsheet is the same width as the chassis

 

Next pair are 060's so slihtly different - at the 'long' end there is a very clear vertical join between the topsheet and the cab, but at the short end its smooth.

 

Next up is Hornbys prototype, which at least in preservation has been smoothed out completely

 

then one of Preston Docks' examples - obviously the side sheet is somewhat non-standard, but someone is filling the gap between the cab and top sheet.

And the other pair at Preston show that on these the upper sheet isn't blended with the cab, and indeed appears to be sitting slightly lower than the horizontal'crease' in the cab side sheet

 

 

Jon

Edited February 13, 2013 by jonhall

[jonhall]

This example is at Long Marston again, and you can see a very rusty line shows up at footplate level, but no sign of rust in the cab to topsheet vertical join

this is the same sentinal as my first group of three but with the engine cover back on.

 

This example is stripped for restoration in the workshops at Cranmore, showing whats under the skin

 

and this example at Rutland has had the side sheet removed to aid access - the sheet is leaning against the workshop wall and the diagonal bracing can be seen

whilst its sister outside is complete - again this appears to have a narrower body than chassis.

 

Jon

Edited February 14, 2013 by jonhall

[Ruston]

 

 I am starting to believe that some of the rod drive examples have a slightly narrower body than chassis.

The cab on the CD* (chain drive) type are shown in the 1964 Sentinel brochure as being 8ft wide, as is the overall width.

The 0-4-0 and 0-6-0 SR* (rod drive) types are shown as having 8ft. cabs and 8ft. 6in. overall (the frames).

The 0-8-0 SR type is shown as having a cab of 8ft. 6in. and an overall width also of 8ft. 6in.

 

 

* Sentinel's own designations for the classes.

 

And for those who are wondering what kind of loads their CD types can haul.

Edited February 13, 2013 by Ruston

[Michael Edge]

 

 

No matter how hard I look at that photo I can't see where you see the split, but there is no doubt in my mind its there (on SOME locos) I am starting to believe that some of the rod drive examples have a slightly narrower body than chassis. In my next couple of posts I'll look at a few examples of each.

 

Jon

The rod drive locos, 0-4-0 and 0-6-0, have a wider platform, the cab and side sheets are the same width as the chain drive 0-4-0. What you may see as a joint line, depending on the angle of the photograph, is a 3" wide step.

[brian777999]

It looks better with the step... more balanced somehow. I think the Hornby model will have  flush sides as it is probably cheaper to produce.

 

 Was the side sheet removed by the owners or were some made like this at the factory ?

Edited February 14, 2013 by brian777999

[rope runner]

and this example at Rutland has had the side sheet removed to aid access - the sheet is leaning against the workshop wall and the diagonal bracing can be seen

sentside013.jpg

whilst its sister outside is complete - again this appears to have a narrower body than chassis.

sentside014.jpg

 

Jon

 

The locomotive in the Shed is "Graham", ex OIC

The loco outside is "Betty", also ex OIC

 

The Crimson Lake loco at Long Marsdon is probably "Jean" (also formerly OIC), which is also now at Rocks by Rail (formely The Rutland Railway Museum).

 

It may interest people to know that "Graham" was originally supplied with vacuum brakes, and additional weights fitted inside the frames to increase traction. The other two locos worked the Quarry lines, while "Graham" worked the "mainline" to the exchange sidings. There is also "Barabel" which is on the Neve Valley, but has had modifications to its bonnet.

 

All of the nameplates came off the steam locomotives which these Sentinels replaced on the IOC.

 

Paul A.

[brian777999]

The locomotive in the Shed is "Graham", ex OIC

The loco outside is "Betty", also ex OIC

 

I wish Hornby had copied Betty ; that is just what I am looking for.

Edited February 14, 2013 by brian777999

[rope runner]

If the Hornby model looks like Betty than I will probably buy four of them !

 

I'm afraid not, the Hornby model is chain-drive, not rod-drive.

 

I'm sure it'll be a lovely loco though, well worth getting for its price

 

Paul A.

[RJL]

Moorgreen Sentinel at Langley Mill.

[Michael Delamar]

some shots from Alexandra palace.