Ride quality on new track

[PaulLothian]

Had my first trip from Bathgate to Glasgow the other day, and was extremely surprised and delighted by the smoothness of the ride in a class of train that I had never thought of as smooth-riding. Then we hit the older track from Airdrie westwards, and rocked, rolled and shoogled for the rest of the way!

What makes the difference? Is it to do with starting from scratch, as opposed to relaying on an existing trackbed? Or is it about difficulties in maintenance, or gradual deterioration caused by heavy use?

 

[Ploughman]

Renewals and new installations are designed and installed to the design, with fairly tight allowances for deviation from line and level. A crew of bodies is normally behind the tamper recording 6ft, Transfer level every 10 metres and cross levels about every 5 sleepers as a minimum.

Existing track is tamped to a maintenance standard. If you are lucky there might be someone behind checking the crosslevel with not a lot of consideration for line and level.
As to how frequently a stretch of track will see a tamper, ask yourself why 20 years ago the tamper fleet had so many machines and now there is less on maintenance work nationally than used to be in use in a region.
I think every mile of track used to get a visit from a tamper at least every 6 months. Now it depends on the results from the Track Recorder units in the NMT.
Economics rearing its head again.

 

[Hydro]

It's not always the case. A certain chord in Liverpool, installed 2 years ago, was found recently to include severe top defects, crowned off with a 1:71 twist. It was closed immediately. Apparently there were "issues" with the installation. A twist as severe as that should never even be allowed to exist, let alone develop in track so new.

 

[thelem]

As to how frequently a stretch of track will see a tamper, ask yourself why 20 years ago the tamper fleet had so many machines and now there is less on maintenance work nationally than used to be in use in a region.

Is this causing problems? From what you've said it could equally be the result of more hard-wearing track, or just maintenance being done when it was needed rather than on a schedule even if the track was still perfectly good.

 

[Ploughman]

The track is just as hard wearing as it ever was.
The major difference now is sleeper spacing and in some cases increased ballast depth.
As for maintenance being done when needed I think you had better have a look at some of Old Timers comments on the subject.

As for the tampers admittedly they do have a faster rate of working and are equipped with various computerised systems to ensure top and line are fit for speeds but if you examine the trackside datum plates especially those on the OHLE masts these were marked up on registration of the masts or when a new design has been implemented.
Once they pass to maintenance how often are these dimensions checked and the track then reinstated to its design alignment?