Oxford Rail N7

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RJB
Posts: 3
Joined: Sun Jun 09, 2019 3:53 pm

Re: Oxford Rail N7

Postby RJB » Sun Jun 09, 2019 9:16 pm

Hi,
I am new to this or any forum - just wondered whether anyone out there has tried the new Oxford Rail N7 on gradients? Having just acquired one, I have tested it unladen on my 4%, 4th radius gradient to find that it clunks with rotational regularity whilst ascending. It is fine on the flat, if a little whiney. I know the gradient is fairly steep but most other locos (Bachmann/Hornby/Lima, etc.) will cope with it. I'd like to know if my loco has a fault or whether it is a design issue. Any comments welcome. Thanks.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Mon Jun 10, 2019 9:30 am

Welcome aboard.

On my grand experience of one (1) purchase of an N7 so far, and use on the 1 in 80 straight line gradients of my layout, I haven't experienced the problem described. It pulls well enough thanks to the weight. (It took some hours of running to completely quiet the gear whine when running fast BTW.)

I can see a design issue though, if used on a steep gradient and tight radius curve combination. The leading axle rocks slightly, a spring acts on the centre of the axle to produce this effect which is good for maintaining pick up. The model has rigid side rods too (most newly tooled six+ coupled models have jointed rods). Between these two, and the 'wind' on the track produced by a steep gradient on a tight curve, all the slack between the rigid side rods and crankpins is probably taken up because the leading axle will be permanently canted relative to the other two driven axles while on this section of track, and that leads to a slight cyclic bind that you are hearing as a clunk.

I wouldn't want to run a mechanism like that, as a regularly applied stress of this sort won't do the mechanism any favours. If the mechanism is robust enough throughout, then it may do no more than wear itself enough clearance between the crankpins and rod holes so that the clunk becomes inaudible.

There are practical ways around this on the loco, but these involve modifying the mechanism. Making the leading axle rigid will fix it, but the loco is then running on just three wheels on the curved gradient. Alternatively making jointed side rods will allow the rocking axle to be retained but increase the slack in the side rods to hopefully eliminate the bind. The better alternative is to ease the gradient and/or increase the curve radius: all your locos will thank you for this!

RJB
Posts: 3
Joined: Sun Jun 09, 2019 3:53 pm

Re: Oxford Rail N7

Postby RJB » Mon Jun 10, 2019 11:29 pm

Thank you for your very complete analysis Bigmet - much appreciated! Unfortunately the confines of space will not permit a lesser gradient or radius on this particular part of my layout and I am prepared to accept that some locos will have to be route specific. Your suggestions re the front axle and side rods make perfect sense and I agree that it wouldn't be a good idea to operate the loco regularly in this manner. Modifying the side rods sounds like the better option but for now I'm happy to understand what the problem is and run it accordingly. Pity though because with the traction provided by the weight of the loco I thought it would pull well up the gradient. All this aside, I really like this engine and the quality feel due to the part metal body is very pleasing. I also have an innate NE/LNER bias so it scores well there too! Thanks again.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Tue Jun 11, 2019 8:24 am

Route restriction was a reality, so having to restrict a loco from a location is a nod to that, and a chance to introduce some operational complexity. I would think that all of the J50, L1 and N2 from Hornby and the V1/V3 in current form from Bachmann would have no trouble on the gradient (jointed rods on all of them) all reasonably heavy, and the N2 particularly can take more weight.

Since you mention NE, we have yet to see how well Bachmann do with an 0-4-4T, until their MR Johnson 1P is released. The TMC commission of the NER design G5 from Bachmann will be their next 0-4-4T, an ideally flexible loco for a curved gradient; but it will need a well arranged mechanism to pull well. The prototype was noted for its capability over the line now operated by the NYMR, and that is properly steep, so the model has something to live up to...

RJB
Posts: 3
Joined: Sun Jun 09, 2019 3:53 pm

Re: Oxford Rail N7

Postby RJB » Tue Jun 11, 2019 10:01 pm

Yes, the V1/3 I have, which is an older Bachmann, copes pretty well, as does the N2. Actually the best loco up to press for my 'asking a lot' route is the Hornby Railroad D49 which will pull 3 Gresley suburbans up it no problem. Also most diesels have no issues and will haul 4 coaches up with relative ease. Funny you should mention the NYMR as it is about 5 miles from my house so I'm very familiar with that particular line. I believe the grade up from Grosmont to Goathland is about 1:49 (which makes mine seem almost reasonable) so you are spot on with your comment. The G5 will indeed be an interesting addition which I shall look to acquire at some stage. Also very much looking forward to the 1:1 scale G5 which I understand is progressing well at Shildon. Can't wait to see it in action!

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Wed Jun 12, 2019 9:08 am

Lovely spot, I envy you having one of the best preservation lines so nearby. I am in a 'dead spot' for good preserved railways, a two hour drive from the Bluebell, NNR and GCR...

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Thu Sep 05, 2019 9:50 am

Clearly the round top boiler version isn't arriving in August! But there's a revised date, somewhere in October - December 2019, and we are now getting two BR versions, the early crest we have known about since forever, and a (very late) late crest example.

I will have to put a blob of black and filth over the OHL warning patches for a start, never seen on a GN section allocated N7, and also overpaint the white band around the chimney top, when I get down to renumbering this loco to whatever is the best fit for one of the Hatfield locos. This was the last class of steam loco I saw - struggling - on the Hertford branch as it tried to get the tip train restarted while on the little hump made by the level crossing over Ridgeway. Real 'Thomas and the troublesome trucks' stuff for young boys.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Sat Oct 19, 2019 8:16 pm

The BR early crest model has been available a few days, and I picked up the one I ordered earlier today. Good, very. Some small modifications and renumbering are in store to make it one of the Hatfield allocation. Already removed the steam heat piping, perpetual summer on my layout; it has to be pulled out of a chassis block location under the cab anyway to allow decoder fitting. Operation every bit as good as my first example. I intend having a threesome; a late surviving belpaire boilered in externally poor condition early crest, this new one in early crest somewhat grubby, and the late crest model recently returned from overhaul and pretty smart.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Wed Oct 23, 2019 9:14 am

One slight alarm to report while this loco was on its DC running test, a sudden acrid smell of incineration. 'Oh dear' I thought, but the model kept rolling along trailing some rather nifty smoke for a few seconds. Not the motor but a very toasted capacitor mounted on the decoder socket blanking plug, so no harm done. On completion of DC running it got a Zimo MX600, hardwired to the very neatly laid out board. As a fully insulated decoder, the Zimo is rather more convenient than the Lenz standard for the small and all metal bunker void directly above the board.

Good internal layout for DCC by Oxford Rail, both the board and the provision of a decoder void above. The largely metal body and neat drive line deliver smooth running with ample traction. If the J27 is to the same standard, there will be much rejoicing I feel.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Tue Dec 17, 2019 10:15 am

For any who want to know, disassembly of the body isn't too difficult. (I wanted to get inside the cab to very much tone down the clean cream paintwork. The reality of a working steam loco is that between the smoke at lighting up, and the soot that leaves the firebox while running, coal dust from firing, oil from any steam escape, a dark grey with a hint of brown deposit quickly covered any paint; unless the crew(s) were heroically dedicated to keeping 'the office' clean - some would do this.)

With the body off the mechanism look at the underside toward the front, remove the four crosshead screws. Now use a good light to inspect the inside of the bunker. See the two lugs from the rear spectacle plate? Push them out. And now the quite complex plastic parts assembly of smokebox on its saddle, boiler and cab spectacle plates and roof just lifts away from the one piece cast footplate, sidetanks and cabsides/bunker exterior.(If you have a condensing version lift the pipes out of the tank tops before removing the body.) All very neat and tidy, reassembly is likewise straightforward.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Thu Oct 08, 2020 12:24 pm

Still waiting for the late crest N7. Progress very slow at Oxford, couldn't be because the boss is running Hornby could it?.

The oldest of my 2 Oxford N7s managed an accident a couple of days ago, got into a fight with a queen wasp (presumably looking for a snug berth for the winter) and came out of it still going, despite the carrying wheels off the rail, with the wasp mangled. Now the pleasing thing: this LNER liveried model has been crudely repainted to represent Hatfield's 69695, a late surviving Belpaire boilered member of the class, which worked the last scheduled Hatfield - Hertford and return passenger service. It got a dirty black skim of paint all over to hide its LNER identity, and represent it in very run down condition, then new BR crest and number transfers (also very grubby) on top. The paint has all by itself began to allow the old identity to show through a little, very satisfactory effect.

I humbly accept the Fluke Modelling Prize, 2020.

Ex-Pat
Posts: 2185
Joined: Tue Feb 08, 2011 10:51 pm
Location: Dundalk Ireland

Re: Oxford Rail N7

Postby Ex-Pat » Thu Oct 08, 2020 3:46 pm

Bigmet wrote:Still waiting for the late crest N7. Progress very slow at Oxford, couldn't be because the boss is running Hornby could it?.

I humbly accept the Fluke Modelling Prize, 2020.


Surely not without a photo first, please?!

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Thu Oct 08, 2020 4:08 pm

Ex-Pat wrote:
Bigmet wrote:Still waiting for the late crest N7. Progress very slow at Oxford, couldn't be because the boss is running Hornby could it?.

I humbly accept the Fluke Modelling Prize, 2020.


Surely not without a photo first, please?!

My lack of any kind of digital photography kit makes this problematic...

Mind you, if someone wishes to start a 'Fluke Modelling Prize' thread and anyone posts an entry with pictures of an unplanned, unexpected, good outcome I will happily concede the palm.

Bigmet
Posts: 9117
Joined: Tue Aug 14, 2007 2:19 pm

Re: Oxford Rail N7

Postby Bigmet » Tue Feb 02, 2021 11:37 am

Bigmet wrote:Still waiting for the late crest N7...

Wait over, and my third and final purchase of this model is now 'on shed' (that's sufficient to operate the branch and mainline work that this class were on) while my old and worn out kitbuild lurks on shed representing one of Hatfield's numerous allocation of 0-6-2T's on 'shed day' for essential maintenance. Particularly pleasing, this last one is the best yet for running; smooth and silent straight out of the box, the only noise is the wheels on the rails.


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