Page 22 - May June 2000

CONSTRUCTOR’S CORNER #2...
The loco drivers and motion were removed and the Puffers axlebox guides soldered up. A triangular needle file was used to thin the hornblock guides until they were a comfortable fit in each hornblock cut-out. At this point I was assuming that the substitution of the Puffers units would match the centres of the wheels and as it turned out it did... ...phew! The hornblocks themselves were slightly too tight for the Sharman Wheels axle and needed a 1/8 ins reamer. The guide units were then cemented in place with a smear of Araldite and left overnight to set.
From John Wright...
The following is an extract from my website ‘P87 Pages’ which takes the form of an ongoing diary recording the progress (or sometimes the lack of it) in developing ‘Federal Street’, a layout using Proto87 standards.
Locomotives in P87
This is an account of the conversion to Proto87 of ‘Federal Street’s’ first steam outline locomotive, a Pennsylvania Railroad A5s 0-4-0 switcher. ‘Federal Street’ is a small switching layout being constructed to P87 track and wheel standards. The layout follows Pennsylvania Railroad practice c. 1948 to 52 and is based on the Whitehall Branch in Southside Pittsburgh on the Pennsy’s Monongahela Division. The branch had street running and several spurs which wound their way in and out of various industrial locations.
It is not an account for the purist as it uses driving wheels to P4 standards ( Sharman Wheels) which, apart from being incorrect for the A5, have a slightly overscale tyre width and flange. Also, in order not to overcomplicate matters, no attempt has been made to reduce the width of the tender trucks. Rather it was seen as an exercise in getting a steam outline locomotive running on the layout and to see what problems might be encountered. The A5 was chosen as it seemed, on paper at least, to offer few problems in this my first conversion. And so it proved. The Sunset A5 is relatively cheap for a brass import and plenty are around on the secondhand market, too. In the light of all the many things considered during the construction of a layout it is debatable if any further alterations to the model will be made.
Prototype Info
The sheer size of the Pennsy’s A5s* switchers might come as a bit of a shock to those used to our Barclays, Hawthorns and co. here in the UK. The A5s was a class of 47 locomotives built at Altoona between 1916 and 1924 for work on tightly curved tracks on the system. Mostly they worked on the Eastern section of the PRR in New York, Philadelphia. But as ‘Federal St.’ is set in Pittsburgh I have to resort to ‘modeller’s licence’ and assume a scenario that maybe the loco is on trial on the Whitehall Branch. And for such a short period that the composers of historical records failed to notice.
Cylinders 20” x 24” • Driving Wheels 4’ 2” (dia) • Pressure 185 psi • Superheating Surface 219 sq. ft. • Weight (eng. & tender) 131,750 lb. • Tractive force 30,190 lb.
As these ‘tiny’ locos had a wheelbase of only 7ft 3ins they must have ridden like the proverbial bouncing cork!
* The ‘s’ suffix denoted a superheated
loco on the PRR.
Parts List
1x Sunset HO A5s PRR 0-4-0 Switcher (Prestige Series )
4x Sharman Wheels 14mm driving wheels (Millimeter Range)
Code M426
1x Pack of Puffers Flexichas Hornblocks (for 1/8 ins axle)
Code CG001 & CG002
1x NorthWest Short Line 28:1 ratio Idler Gearbox (for 1/8 ins axles) Code 142-6
2x NorthWest Short Line “Wimpy” HO loco driver springs
Code 1400-4
1x NorthWest Short Line Universal Coupler set (2.0mm & 2.4mm) Code 482-6
1x NorthWest Short Line 33 ins P87 wheelsets (pack of 4)
Code 37617-4
Plus a selection of hand-tools, mini drill, needle files, soldering iron, epoxy resin (Araldite), 1/8 ins reamer etc.
Proto 87
Conversion Method
Purchasing a brass locomotive results in a considerable investment and I didn’t want to alter any parts that would prevent the loco being returned to its standard HO form. This ruled out re-profiling driving wheels and dis-assembling the original gearbox. Not using the original drivers meant that I would have to not only find suitable new driving wheels but also a set of axleboxes to match the rectangular cut- outs in the A5 frames. Being a lazy so and so has definite advantages at times as my first reaction was to look through the ‘junk’ box to see if there was anything that would do the business. Hoarding stuff may not be the sole preserve of railway modellers but we must come pretty near the top of the league. And wouldn’t you know it, a set of Puffers Flexichas hornblocks were discovered to be an almost exact match.
I think it’s fair to say that the main focus of this conversion centres around these parts (which fortunately are still available). There are other makes of axleboxes but I haven’t tried them as yet, nor can I vouch for the hornblock cut-outs being the same dimensions in other brass locos. Any feedback will be appreciated.
􏰁 1 Puffers Flexichas etching & hornblocks
􏰂 2 Hornblocks in place on the chassis. The LHS hornblock has been turned around to show to the camera the bracket that had to be soldered onto each each one to take the small coiled springs used in American brass loco suspension.
In order to make use of the coiled springs suspension as found almost universally in Japanese and Korean brass locos a small bracket made from 2mm brass angle had to be soldered to the top of each hornblock. If a thicker hornblock was available this wouldn’t have been necessary. The original springs were left in the front hornblocks as this wheelset wasn’t to be allowed much movement. NWSL “wimpy” springs were substituted at the rear. The hornblock guides on the outside of the loco frames were seen to be slightly proud of the hornblocks and the opportunity was taken at this stage to file them flush. This action would stop any edges catching on the insides of the the driving wheels.
􏰂 3 Ventral View of the frames showing the new crankpins made for the driving wheels and also the removal of plastic at the bottom of the gearbox for clearance purposes.
Some concerns with the Sharman Wheels were encountered during the conversion. The driving wheel crankpins were too small to take the A5’s combined rods and Walschaerts eccentric crank so new ones had to be fabricated. As the Sharman Wheels’ crankpins are moulded into the wheel and I did not want to risk cutting them out, I used small brass tubing (1.5mm outside dia) which was Araldited in place around the original. These new crankpins were slightly tapered at the end with a needle file to give a good force fit with the eccentric. The front coupled wheels’
22 ROUNDHOUSE