Building a C Class

[lucas]

Not much to share in terms of progress of late. I have been working in parallel on both the chassis and some detail parts, but I'll wait until I have a bit more progress before showing that off.

In the meantime, I thought I’d share some research I’ve been doing on the differences between the Crossley- and GM-powered locos. I’ll be modelling the original Crossley-engined locos, but many of the best photographs are much more recent. So it’s good to know what has changed and what hasn’t so I know which photos I can rely on. Also, I just find it interesting  

There’s a fantastic video from Gerry Conmy on YouTube with a lot of pictures showing the re-engining process: https://www.youtube.com/watch?v=eL1r5Ipeb1w. I have posted some screenshots of the video below where I haven’t been able to find other images, but there is a lot of good material in the video and it’s well worth a watch.

Roof changes

As I mentioned in my original post, the roof seems to have undergone the most drastic changes during the re-engining process. It is also one of the least photographed parts of these locos, but probably the most visible on a model.

As-built, the C class rooves had 5 removable panels. Starting from the no.1 end (the radiator end) there is a small panel containing a relatively small 6-blade radiator fan, a small panel containing the header tank filler, the largest panel with some blank space and the engine compartment vents, another large panel containing the generator compartment vents and the exhaust, and finally another small featureless panel.

The vents on the engine compartment roof are similar to those on the A class and allow some ventilation for the engine since neither loco has any vents on the body side.

The generator compartment roof vents are unique to the C class. The one on the left-hand side seems to be for the exhauster; the A class has an extra grille on its body side for the same purpose. The one on the right is less obvious. It could be to allow some ventilation for the load regulator’s resistor banks which are on that side, or perhaps it is just there for symmetry. The A class doesn’t seem to have any equivalent ventilation near its load regulator as far as I can tell.

The exhaust actually stretches above the generator and exits on the far opposite end of the generator compartment, as can be seen in this picture with the two larger roof panels removed. Note the loco is facing the opposite direction compared to the image above.

When the much more powerful GM engines were fitted, the class had much larger radiators and a larger 8-blade fan installed. To accommodate this the roof panel containing the fan was also enlarged.

The header tank filler panel seems to be the same size, just positioned a little further back due to the larger fan. The filler itself had changed, sticking out noticeably higher than the old one.

The large engine compartment panel was fractionally enlarged and modified to accommodate the new engine. The vents seem to be the same size, but were moved to the opposite end of the panel, nearer the radiator fan on the no. 1 end. A hole was cut between the two vents for the exhaust silencer with two slot-shaped exhaust ports. Unlike the Crossley, the exhaust sits right above the engine. An extra 'hump' was also added on one side behind the vents to cover the new Roots blower. The A class has two such humps, one on either side, but the C class has just one.

With the larger fan and engine vent panels, the generator vent panel was cut down to compensate. The panel and the vents it houses were reduced to around ⅔ size post-transplant. The two holes for the old exhaust ports were also removed.

The last small blank panel seems to be the only one that went completely unchanged.

Here is a picture demonstrating the changes. You can clearly see the weld lines from where things were modified, including the two spots where the old Crossley exhausts used to be.

Other exterior changes

As mentioned, the GM engine required the fitting of larger radiators which also meant the radiator grilles got enlarged by a considerable amount on both sides.

A new external fuel gauge was also fitted on either side requiring a small cutout in the bottom edge bodywork near the middle. Another smaller pill-shaped cutout nearer the no. 1 end was removed on some of the locos, but not all. I think this was probably to access the radiator drain valve, but I’m not entirely sure.

Along with the transplant, the locos underwent a few other changes during the process. This included large GM headlights fitted to the ‘forehead’ on either end of the loco. This is probably the most obvious external change, but there were quite a few others too.

As built, they had a fairly minimal amount of equipment on the buffer beam, just a vacuum hose. During the transplant an MU (multiple unit) socket and air brakes were fitted to allow them to operate push-pull trains with the AEC former-railcars. A handful had previously been fitted with ETH (electric train heating) sockets, but these were all removed during the transplant.

The locos were also fitted with staff catchers. Unlike the A class, the Cs never had them previously.

And of course, they were given a new lick of paint and a new B2XX classification to denote the increased power.

You can clearly see most of these changes comparing these two photos:

Note 206 did not have small pill-shaped opening on the body side removed, while most others did. Perhaps if I was modelling a GM-engined loco I’d have the motivation to go trawling through photographs to figure out exactly which ones had this opening covered up and which didn’t. The picture below shows C201 in Inchicore post-transplant but pre-repaint, and you can clearly see this opening has been freshly covered up:

https://www.flickr.com/photos/irishrailwayarchive/54778612658/

Maybach Transplants

C233 and C234 were given initially Maybach engines in the mid-60s. At the time GM weren’t willing to sell engines on their own, just complete locos. Apparently, they were worried that GM engines fitted in iffy machinery would harm their reputation. They did of course change their minds a few years later when CIÉ had proven to be a loyal customer.

The Maybach engined locos shared some exterior details with both the Crossley and GM locos, but also had some of their own unique changes.

Similar to the GM locos, the Maybachs had a larger fan installed on a suitably enlarged roof panel. However, the rest of the roof layout stayed mostly the same as before. The vents were perhaps slightly repositioned, and it seems like some of the blank space on the largest panel was removed to make room for the larger fan.

I can’t find any good images of the roof showing the exhaust. I seem to remember stumbling upon an image in the past showing a singular round exhaust, but I could be mistaken.

Larger radiator grilles were present on the sides similar to the later GMs. The same external fuel gauge was also fitted. And the pill-shaped hole seems to have stuck around on both 233 and 234 until their later GM transplants.

An MU socket and air brakes were added to the Maybachs too, but the MU socket was in a slightly lower position. This required relocating the dummy coupling for the vacuum hose to the opposite side so it wouldn’t be in the way.

One of the most obvious unique differences is the removal of one of the ‘porthole’ windows on the right side of the body. They also did not receive either the GM headlights or the staff catchers that the later rebuilds did. However, they did receive the B2XX reclassification.

Here are some pictures illustrating the differences between front ends of the 3 variants. The first picture shows a Maybach- (left) and Crossley-engined loco (right) side by side. The second shows a Maybach- (centre) and GM-engined loco (right), with a GM-enigned Ar lurking in the background on the left.

https://www.flickr.com/photos/152343870@N07/52050288065/

The two Maybachs did receive GM engines nearly 10 years after the rest of the fleet, along with their GM headlights. But I can’t seem to find any pictures of them with staff catchers, so they may never have had these.

They did not lose all their Maybach-isms either. Here is are some photos of 233 and NIR 109 (formerly 234) showing the missing window and relocated vacuum hose still present long after being re-re-engined:

https://www.flickr.com/photos/irishrailwayarchive/54777525252/

https://www.flickr.com/photos/152343870@N07/52094277983/

 

Edited 2 hours ago by lucas
Formatting

[Mol_PMB]

Excellent detective work - many thanks for sharing this! 

The MU sockets on the two Maybachs allowed them to work in multiple with the B141 and B181 classes. I’ve seen at least one photo of a ‘mixed pair’.

They worked a Dublin-Limerick link for much of their life as Maybachs. So no need for tablet catchers. 

 

Couple of pics of 233 in Supertrain livery while still Maybach-engined:

Edited 3 hours ago by Mol_PMB

[lucas]

15 minutes ago, Mol_PMB said:

The MU sockets on the two Maybachs allowed them to work in multiple with the B141 and B181 classes. I’ve seen at least one photo of a ‘mixed pair’.

That's good to know, thanks! I hadn't come across photos of them operating in multiple or push-pull so I was wondering what they were intended for.

 

Edit: I actually found (what I assume is) the picture you're talking about. B233 working multiple with B192 on p. 36 of Irish Metro-Vick Diesels by Barry Carse

Edited 3 hours ago by lucas

[Mol_PMB]

17 minutes ago, lucas said:

That's good to know, thanks! I hadn't come across photos of them operating in multiple or push-pull so I was wondering what they were intended for.

 

Edit: I actually found (what I assume is) the picture you're talking about. B233 working multiple with B192 on p. 36 of Irish Metro-Vick Diesels by Barry Carse

Yes, that's the one. I was going to look out the reference once I'd got some transfers onto one of my new Park Royals, but you beat me to it!

[Horsetan]

1 hour ago, Mol_PMB said:

...

I'm sure I've seen that type of bogie on something else before....

[Mol_PMB]

6 minutes ago, Horsetan said:

I'm sure I've seen that type of bogie on something else before....

Now that @lucas is putting all the effort in, I’d be willing to place a small bet on an IRM C class being announced within the coming year!

The sort of daft thing I’d do is a Maybach conversion. 

[lucas]

20 minutes ago, Horsetan said:

I'm sure I've seen that type of bogie on something else before....

Don't get me started on the bogies, I've noticed quite a few variations there too  

Expect another post on that once I've had a bit more time to research

[Mol_PMB]

11 minutes ago, lucas said:

Don't get me started on the bogies, I've noticed quite a few variations there too  

Expect another post on that once I've had a bit more time to research

Indeed. As with the A class, originally fitted with sandboxes. 

When they were silver and still fairly clean, the details are easier to see. 

[lucas]

16 minutes ago, Mol_PMB said:

Indeed. As with the A class, originally fitted with sandboxes. 

When they were silver and still fairly clean, the details are easier to see. 

Yes that is the most obvious difference, but there are a few others.

I have come across at least 3 different variants of the bogie frame. There doesn't seem to be any clear pattern for which appeared on which loco, with two different variants often appearing on the same loco. In fact they seem to have gotten swapped around over the years, presumably when multiple locos were in Inchicore at the same time they ended up with each other’s bogies. I have a spreadsheet of which loco had which bogie type(s) throughout the years, but it's still a work in progress.

I'll share more details when I have a better picture myself. All I'm saying for now is IRM better have their eyes on the ball

Edited 1 hour ago by lucas
A word