Strip glazing vs Rounded windows

[driverd]

Hello all,

Just a quick question really. What has inspired the move away from strip glazing to rounded windows?

Just incase I'm not using the correct technical terms, for "strip glazing" I'm thinking of class 170s, Class 375s, Class 460s.

Rounded windows I'm thinking newer units such as Class 172s, Class 387s and Bombardier aventras.

Personally (and I'll try and avoid opening the subjective, personal opinions can of worms here), I much prefer strip glazing as I find it looks a lot tidier (though many TOCs paint a black band around the windows which somewhat replicates the look, thinking TPE 185s etc). What I'm asking, however, is if there is a technical reason that strip glazing seemed popular around the early 00s but seems to have fallen out of favour again?

 

[swt_passenger]

Hello all,

Just a quick question really. What has inspired the move away from strip glazing to rounded windows?

Just incase I'm not using the correct technical terms, for "strip glazing" I'm thinking of class 170s, Class 375s, Class 460s.

Rounded windows I'm thinking newer units such as Class 172s, Class 387s and Bombardier aventras.

Personally (and I'll try and avoid opening the subjective, personal opinions can of worms here), I much prefer strip glazing as I find it looks a lot tidier (though many TOCs paint a black band around the windows which somewhat replicates the look, thinking TPE 185s etc). What I'm asking, however, is if there is a technical reason that strip glazing seemed popular around the early 00s but seems to have fallen out of favour again?

IIRC when this came up before they went back to conventional glazing, because repairs were much easier, basically replacing a framed window was much quicker and easier than the bonding process for the glass strips.

 

[skyhigh]

It's much easier, cheaper and faster to replace a gasket window compared to a bonded one. With a bonded window you generally have to wait up to 24hrs for the adhesive to cure before the vehicle can be moved again but with a gasket the vehicle can go straight back into service.

 

[theageofthetra]

It's much easier, cheaper and faster to replace a gasket window compared to a bonded one. With a bonded window you generally have to wait up to 24hrs for the adhesive to cure before the vehicle can be moved again but with a gasket the vehicle can go straight back into service.

When you have a car windscreen replaced, they are all bonded these days, why is there no requirement to wait 24hrs?

 

[Neptune]

It's much easier, cheaper and faster to replace a gasket window compared to a bonded one. With a bonded window you generally have to wait up to 24hrs for the adhesive to cure before the vehicle can be moved again but with a gasket the vehicle can go straight back into service.

Less down time replacing a window = less shortage of units = chance of a cancellation.

 

[Mikey C]

Bus bodies in the UK had a similar development path, going from gasket glazing to bonded glazing, to then return to gasket glazing, presumably for similar reasons.

Subsequently a number of buses in the UK have returned to bonded glazing. I recall Alexander Dennis saying that they used a new process enabling windows on the E400MMC to be replaced quickly.

 

[Bletchleyite]

With buses there's more of a reason to go back to bonded - it provides added body strength which reduces rattles and bangs.

Rail vehicle bodies are stronger so don't require that extra support in the same way.

 

[Bald Rick]

When you have a car windscreen replaced, they are all bonded these days, why is there no requirement to wait 24hrs?

Gravity and air pressure when moving forward help. Neither help on train side windows.

 

[dgl]

With buses there's more of a reason to go back to bonded - it provides added body strength which reduces rattles and bangs.

Rail vehicle bodies are stronger so don't require that extra support in the same way.

Not when the windows themselves rattle!, the upstairs emergency windows on our 65 plate E400MMC's are terrible rattlers.

 

[driverd]

It's much easier, cheaper and faster to replace a gasket window compared to a bonded one. With a bonded window you generally have to wait up to 24hrs for the adhesive to cure before the vehicle can be moved again but with a gasket the vehicle can go straight back into service.

So just to understand the process here - a gasket window essential requires removal of the frame, new glass insert and replace the frame?

Mean while, stip glazed windows require an application of adhesive and to stand still?

That being the case, what was the logic in moving towards strip/bonded glazing back in the 00s? Just astethetics?

 

[Doomotron]

I'm pretty sure the correct term should be ribbon glazing, but I might be wrong myself.

 

[norbitonflyer]

That being the case, what was the logic in moving towards strip/bonded glazing back in the 00s? Just astethetics?

Probably - the 460s for the premium Gatwick Express had them (along with the "Darth Vader" nose cones) but the contemporary 334s and 458/0s didn't.

 

[Prime586]

That being the case, what was the logic in moving towards strip/bonded glazing back in the 00s? Just astethetics?

The automotive industry changed to bonded glazing as it was cheaper (it could be installed by robots), less leak prone and had lower drag, and it's use as a structural element added stiffness to the upper bodyshell (which allowed less metal to be used). I imagine a lot of the same reasons led to it's use in rail vehicles.

 

[Goldfish62]

When you have a car windscreen replaced, they are all bonded these days, why is there no requirement to wait 24hrs?

Because the glue cures a lot quicker these days. Same with buses, hence the now total move away from gasket glazing. Maybe a different type of glue that requires longer curing is used on railways.

 

[BRX]

These ones (photo of windows on mk5 sleeper) - are they some kind of hybrid? They have what looks like a kind of gasket but they also have the broad black bands around the perimeter of the glass itself, which usually indicate glued-in glazing.

 

[Bletchleyite]

View attachment 154564

These ones (photo of windows on mk5 sleeper) - are they some kind of hybrid? They have what looks like a kind of gasket but they also have the broad black bands around the perimeter of the glass itself, which usually indicate glued-in glazing.

Fairly sure the black bands are just to hide the fact that the inside trim is smaller than the hole in the bodyside.

On some designs of bus you also get it to prevent "upskirting" from the outside where the windows would go below seat level in the high floor section.

 

[Goldfish62]

Fairly sure the black bands are just to hide the fact that the inside trim is smaller than the hole in the bodyside.

Maybe so in this case, but the black border on bonded glazing is essential as it's that that the glue bonds to. The dots on the border are called frits and are designed to draw heat away from the border reducing the risk of debonding.

 

[TrainBoy98]

Maybe so in this case, but the black border on bonded glazing is essential as it's that that the glue bonds to. The dots on the border are called frits and are designed to draw heat away from the border reducing the risk of debonding.

You learn something new everyday! I've always wondered what the "dots" were called/for!