Re-Building a Simplex Loco

[julian atkinsParticipant @julianatkins58923]

Stew has done a very good job on a design that despite it's unexpected popularity is not a good design. it is usually referred to in club circles as 'Complex'.

i have driven many examples (never 'sparkling&#39 and had quite a hand in making a Super Simplex (larger boiler) but with the Simplex cylinder dimensions. Don Young and i had many discussions together about the original design, most of which are quite unrepeatable!

Don Young did his Jack and Jill in 5"g which are far superior designs IMHO but very rarely seen.

on the original Simplex boiler design the Aussie guys would not approve the design. for the UK i re-designed the crownstays and a few other bits for the own example i was involved in.

cheers,

julian

[David WassonParticipant @davidwasson11489]

I'm not sure why anyone would ever call a Simplex a "Complex". It seems no more complex than any other similar 0-6-0 locomotive.

I'm sure one reason for it's popularity is the series of build article(s) that appeared in ME. For someone building a first locomotive and knows nothing about construction, these articles are very important. Outside slide valves, and Walschaert's valve gear make for a good first locomotive.

I finally got mine running on air today!

Julian, could you share some of the "other bits" you re-designed?

[julian atkinsParticipant @julianatkins58923]

hi david,

congratulations on getting yours to run on air yesterday!

oh dear, where do i start!

the box type expansion links are the most difficult type to make.

ordinary pivoted lifting links to radius rods would have been far easier.

the original pump design and its problems and foul ups have been discussed at length previously.

there is a particular problem in positioning the expansion link trunnions.

the one piece bunker/cab side/side tank was easy to draw but awkward to make and even more difficult to dismantle.

martin evans' stupid notion of making the side tank base the running boards.

cylinders far too large in bore.

i can PM you re the boiler. i dont want to bore other forum members.

cheers,

julian

[Stewart HartParticipant @stewarthart90345]

Posted by julian atkins on 08/02/2016 11:12:46:

 

oh dear, where do i start!

1:- the box type expansion links are the most difficult type to make.

ordinary pivoted lifting links to radius rods would have been far easier.

2:- there is a particular problem in positioning the expansion link trunnions.

3:- the one piece bunker/cab side/side tank was easy to draw but awkward to make and even more difficult to dismantle.

4:- martin evans' stupid notion of making the side tank base the running boards.

5:- cylinders far too large in bore.

i can PM you re the boiler. i dont want to bore other forum members.

cheers,

julian

These are warranted points, but to be fare, the Simplex is a simple no nonsense design, yes it has its failing but what design hasn't, but its failings can be worked round or just accepted, but it has many good points as testified by the many that have been built. There is no getting away from the fact that most loco built to the design are good runners, I've seen 6 steamed at our club 4 do regular duty at open day and children's parties hauling two full carriages, the fifth I saw steamed once when it had its boiler tested, this was built by the owners grandfather and was one of the nicest finished Simplexes I've seen, the owner has since moved out of our area. The last the owner struggled to keep it in steam, and for one reason or other was unable to persist with it, if he had I'm sure that would have been a good runner also.

To take Julian's points a little further:-

1:- Terry Holland published a simplified link as part of his Farlie series of articles some time ago. Any chance of a simple sketch Julian of the pivoted lifting link design.

2:- I can only say I didn't find it too difficult positioning the trunnions

3:- Yes it is not a very convenient design, but I'm sure a two piece design could be engineered.

4:- Yes the running boards would be better split this is something I did.

5:- cylinders too large:- but they work ?.

For those building or refurbishing a simplex her are a few things that I did to mine.

1:- Added a drain plug to the bunger well tank.

2:- Added oiling points into the steam chest so that oil could be worked into the cast iron cylinders at the end of the day to stop them rusting.

3:- Drilled down the centre off the axles and drilled a cross hole so the axles boxes could be easily oiled.

4:- Cut a hole in the stretcher that covers the axle pump eccentric so that it could be oiled.

5:- Two piece running board so that the slide valves are made easily assessable.

6:- Pole reverser.

7:- Curved blast pipe to direct the exhaust steam better, same with the steam pipe to the cylinders, as for the supper simplex

8:- Did away with the breaks, the drive on trucks have better breaks I couldn't see the point of them.

9:- Fitted automatic drain coxs

A wise old model engineer with many locos under his belt gave me some sound advice:-

"Its your Loco Lad that your building in your sure shed in your own time, so build it any way you want, if you don't like something change it.

Her's some picture of some of my changes.

Stew

 

Edited By Stewart Hart on 08/02/2016 13:21:53

[David WassonParticipant @davidwasson11489]

Thanks for all of the suggestions and updates. To be clear, I am building the Super Simplex.

The expansion links were actually pretty easy to make. I'm not sure if it is the box type or not. In Evans' book it is described as L.N.E.R. 3 piece expansion link. I used the laser cut parts for this, it was actually easier than I expected. I finished them up on a rotary table. The lifting links were easy to make as well. Once again, the lifting arms were fabricated from laser cut parts.

Expansion links were positioned with no problem. There is a hole through both frames that an alignment pin is to be put through. The pin should go all the way through the frames and through the expansion link pivots in the trunnions. This is the position that the brackets should be attached to the motion plates. These alignment holes on the frames are on both the regular and Super Simplex.

Yes, the cab should be made separate from the tanks. Not tough to do. Evans' even suggest doing this for the Super.

The tanks are not really part of the running boards. In fact they are 1/2" above the running boards. Check out the dotted line on page 34 of ME 7 July 1989. The tanks are part of the outer sheet. The outer sheet does come all the way down to the running boards, but, the bottom of the tanks are separate from the running boards.

Yes, the running boards should come apart in two or more sections for access the things underneath. Stewart has done this quite nicely.

Cylinders a bit oversize, yes, as easily shown by the calculations from John Baguley's downloadable spread sheet. I am making mine 1-3/8". Should still be plenty of power. It is interesting that no one else has commented about the Super or regular Simplex running out of steam half way around a track.

Curved blast pipe is standard on the Super Simplex.

As for the boiler, I have not heard of a single failure since it was first designed. Maybe there have been some. This forum would be exactly the place to show or discuss any design changes you have made to improve the Simplex boiler since there are so many folks building, or, re-building a Simplex. No one will be bored. The boiler was supposed to be easier for a first time builder, and the having the crown sheet not connected to the of of boiler does simplify the construction greatly.

[julian atkinsParticipant @julianatkins58923]

hi david,

both Simplex and Super Simplex are over cylindered as we have discussed previously.

the reason why neither design runs out of steam half way round the track is because with the big cylinders they can plod around at 30psi quite happily!

there is another aspect which is that in a lot of designs martin evans was obsessed with providing as much grate area as possible. so in Simplex and Super Simplex the firebox is 'extended' over the rear driving wheels.

you then have the classic Greenly combination of big cylinders and a lazy grate, which annoyed Jim Ewins so much.

your own Super Simplex example should be considerably better than a 'bog standard' made to drawings example, with its smaller cylinder bore.

cheers,

julian

[David WassonParticipant @davidwasson11489]

Hi Julian,

Thank you once again for your comments. I appreciate you chiming in. It would seem like having a large grate area will be a good thing. I do hope I benefit from it. As I may have mentioned before, I am re-gauging my Super to 4-3/4". This will squeeze the fire box by 1/4".

I also do hope that my reduced cylinder bore will be of benefit. Of course, I really won't know the performance until it is finished!

I will keep everyone posted when it happens! By the way, it has taken me 9 months to get from castings and bar stock to running on air! It sounds so good even on just air! I could not be more excited!

David

[Stewart HartParticipant @stewarthart90345]

Thanks Julian for explaining the issue with the cylinder size I understand the issue now:- its the old balancing act of steam production verses rate of use, I can appreciate what you are saying.

Cheers

Stew

[David WassonParticipant @davidwasson11489]

Stewart,

I just wanted to say that I have followed your re-build thread with great interest. What you have done has been quite informational to me. I also appreciate all of the photos, you can never have too many. Even though my loco is a "Super", your photos have been of great help. Thank you so much for posting this!

David

[Bob YouldonParticipant @bobyouldon45599]

Good morning Folks,

Jim Ewins would get all upperty at the very mention of Simplex, probably because it wouldn't fit his formulae, but I wouldn't mind a pound for everyone built and furthermore they've brought delight to thousands of both proud builders and their passengers over the years. Jim always maintained the cylinder bores were too large, well according to his calcs they probably are, but when you've only got 20lb on the clock it'll still pull; what it doesn't have is sufficient superheating surface, not helped by the asymmetric tube layout; the best steaming Simplexs I've witnessed over the years had a symmetrical tube layout with pairs of radiant superheaters.

I think today there are better designs for the beginner to cut their teeth on and my advice to anyone starting on building their first locomotive, if not already a member, join a club, listen, look and discuss before making that decision.

Regards,

Bob

[David WassonParticipant @davidwasson11489]

Hi Bob,

Apparently, the super heater and symmetrical tube layout was recognized by Evan's himself in the original Simplex design. The "Super" Simplex has 6 elements (versus 2) for the super heater and the tube layout is exactly symmetrical. Cylinder bore probably is a little large. 1-3/8" is more correct for the cylinders.

David

[julian atkinsParticipant @julianatkins58923]

i would agree with David that the Super Simplex boiler is better proportioned and has a better tube layout and better superheater arrangement. David's own version with narrower firebox will be even better.

i had thought that Jim Ewins' boiler formalae was directed at the old Greenly designs… in the light of Bob Youldon's remark above perhaps it was specifically directed at the original Simplex!

i have driven lots of Simplex locos and Super Simplex locos to original drawings (none of which 'sparkled&#39. the version of Super Simplex i was heavily involved in building was an attempt to cure the errors of both original designs.

in 1967 the only other beginners 5"g tank engine loco designs available were the Ajax from Reeves, and the Butch from Kennions.

i think Martin Evans was well aware that Simplex didnt come up to expectations. when you met Martin you could never have an in depth conversation with him about his own designs. he would clam up and get very 'iffy'. Don Young on the other hand would stand his ground and fight his corner so to speak. Don's designs are far superior to Martin Evans' designs generally IMHO.

cheers,

julian

[David WassonParticipant @davidwasson11489]

I actually considered both "Butch" and "Ajax". Both look like pretty good 0-6-0 beginners locomotives, perhaps even better than the Super Simplex. The one drawback to either of these locomotives, is there seems to be no "how to" articles. Simplex and Super Simplex have build articles. For a beginner that knows nothing, (like me), these build articles are extremely important. If I had found build articles of either Butch or Ajax, I might have chosen differently. A beginner needs much more than just drawings and castings, Super Simplex has that.

David

Edited By David Wasson on 11/02/2016 01:24:41

[John KinnaneParticipant @johnkinnane64270]

Hi Stew, do you know what size bolts were used to bolt the stretchers to the frames. I have 6BA X 1/4" and the

Length seems a little small, not much thread. Any advise would be appreciated regards John Kinnane.

[Stewart HartParticipant @stewarthart90345]

Posted by John Kinnane on 24/03/2017 03:03:53:

Hi Stew, do you know what size bolts were used to bolt the stretchers to the frames. I have 6BA X 1/4" and the

Length seems a little small, not much thread. Any advise would be appreciated regards John Kinnane.

Hi John

I was reworking a part built Simplex the stretchers as bought were far from square they pulled the frame out of square causing numerous problems, so I made new stretchers making sure the faces were perfectly square and parallel, that solved the problem I was having with the frame.

I fixed the stretchers with M3 screws, you need about 6mm of engaging thread so screws need to be 9mm long.

Where I could I used metric screws: I know members of the "Flat Earth Society" won't like this, but metric being the industrial standard does have a number of advantages, cost for a start, and you can get high tensile, socket headed countersunk or domed or Stainless Steel, which is next to impossible for BA sizes that tend to be universally machined from mild steel and cost an arm and a leg compared to metric.

Hope this helps

Stew

[John KinnaneParticipant @johnkinnane64270]

G'day Stewart thank you for your reply, I had a feeling the 6BA bolts were to small. Interesting I have M3 X 9mm.You were saying that you had to make new stretchers because of squareness issues, mine are lazer cut they are square however the lazer has left a rough edge on them during the cutting process. The problem is that the tolerances are extremely close not allowing me to take any metal off them. The roughness of the edges is minimal should I go with these or make new ones. I really appreciate any feed back on this as I am about to tap and put the frame together.Once again thank you Stew regards John Kinnane

[Stewart HartParticipant @stewarthart90345]

Hi John

I'd checked the squareness if I was you, the laser beam tends to fan out so you don't get a square edge, the better lasers tilt the head to correct this, if in doubt get some more stretchers made a couple of mill over size so you can machine them square. Getting the frame square is a real critical feature as it will impact on the running of the locomotive and the smooth operation of the coupling rods and valve gear. Its easy enough to check the frame for squareness you just have to measure across the diagonals over common points, with a long steel rule what you want is for the two reading to be the same, this will tell you if the frame has been assembled square or not.

Cheers

Stew

[John KinnaneParticipant @johnkinnane64270]

G'day Stew I am taking your advice and I will remake the stretchers giving me plenty of space to mill them square. As you said the stretchers have to be square to the frame or else it will muck everything else up and I am not very happy to take a gamble on these. Thanks mate John

[Ian S CParticipant @iansc]

You could machine them square, and if under size, a packing strip could be put in place, if this is done carefully it's going to take someone with a microscope to see what you'v done.

Ian S C

[David WassonParticipant @davidwasson11489]

Yes, the frame stretchers must be straight, square and parallel. Also, the frames themselves should be straight. If not, they need to be adjusted until they are relatively straight, The stretchers will pull them straight to some extent, but they need to be quite straight to begin with. Straight and square frames are the foundation for everything on the locomotive. This needs to be constructed as well as possible.

David

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