Checking horizontal alignment.

[doggeface]

Since I started into P4 last year the single most difficult thing to measure or even check has proved to be the horizontal condition of track especially in way of pointwork and when other tracks lie between the observation point and the test piece. In my case I chose to build "around the walls" and thus limiting myself to a single sided access.

So, being in a position where the locos are being modified to run on new track - if there is a problem of road holding it poses the question which is it, the track or the loco!

Having been struggling with a Hornby 51XX conversion it rather miffed me when it played up when my other Pannier doesn't! Sure enough there is a track problem but it does not readily show itself when using a curved engineers rule. This mainly due to the rather obvious difficulty of keeping it 's edge verical whilst peering (or trying to peer) under it for the tale tale light!

Having a piece of 20mm x 2mm alu strip handy I decided to make up a saltire form from two 125mm pieces which were slotted and then epoxied together on a flat surface.

PIC_1363.jpg

The idea being that starting from a known "good" part of the track the tool could look ahead just more than a 6 coupled wheelbase length to see where the ends formed the stable triangle. This of course would only indicate a height difference of the distant rail pair as the higher would always form the third point whether it be high or level. Simply using the uneven distant point as the datum would produce an error at the good end which would indicate which way the error is.

PIC_1364.jpg

PIC_1366.jpg

An even more useful addition would be a universal level bubble fixed onto the saltire -- unhappily the only ones found on eBay came from the UK and the seller thought that the world ended at Dover and I have yet to locate some on eBay France.

In the absence of a bubble it means that the check has to be continued by applying the same side ends to the same rail in order to aid in the identification of the high or low point. The area of the variation can then be checked with a straight edge.

The reason for the saltire configuration was to keep contact to a minimum and to enable feeler gauges to be inserted. I had originally tried a length of 20mm "U" channel alu but the far side of it is simply not visible. This cross is fully visible at all four contact points and is easily manoeuvered with one hand.

I would really appreciate any remarks.

Peter
Montarlot

[Paul Townsend]

Surely the length is more like 250mm than 1250?

[doggeface]

Thanks for pointing that out! My enthousiastic finger added the 0 --- it should read 125mm!

Peter

[jasp]

Good idea but instead of the "saltire", why not use a piece of aluminium angle, inverted? This would give the required 4 point contact without having to cut and glue two bits of ally.

[doggeface]

The angle material works in the same way as the "U" extrusion and cannot be observed from the far side. The fundamental reason for the saltire form was to offer all the contact points to view from one position . My boards are 60cm wide and high enough to make anything more than halfway from the edge difficult to work on.

Peter

[Will L]

That's a useful idea thank you.

As a result of trying to solve the same problem, Don Rowland's publishes a piece in the MRJ (or was it snooze?) some years ago about a device to show if there was a difference in hight between rail heads. Basically a vertical post at a perfect right angle to a flat base, with a plumb bob hung from the top of the post. This told you if what the base was sitting on is flat or not. With a bit of basis trigonometry you could arrange a scale that told you how much.

Will

[Russ Elliott]

Will - I think it was called the Don Rowland 'Diplometer'.

[Will L]

Will - I think it was called the Don Rowland 'Diplometer'.

That's the feller

[martin goodall]

I was also going to mention Don Rowland's 'Diplometer' [Should that not have been "Dip-o-meter" ?]

It was written up in Model Railways some time in the early-mid 1970s.

[Tim V]

There is the Mike Clark dodgy track detector as well....

[Rod Cameron]

I was also going to mention Don Rowland's 'Diplometer' [Should that not have been "Dip-o-meter" ?]

It was written up in Model Railways some time in the early-mid 1970s.

There was a postscript article in SN 142.

[Paul Willis]

There is the Mike Clark dodgy track detector as well....

I hear a whisper that earlier this evening someone has promised an article for the News on the building and use of one of those...

Flymo

[Tim V]

A bit late, I've had mine for a couple of years.....

[martin goodall]

There is the Mike Clark dodgy track detector as well....

Oh, yes. I bought one of those. The kit is still in the drawer, waiting for me to get 'a round tuit'.

I had quite forgotten it until I read Tim's note. Must add it to the 'to do' list.

[Tim V]

It does actually work. Note Mike's point in the instructions about using round wheels, though I don't have to say that to you Martin....

[martin goodall]

It does actually work. Note Mike's point in the instructions about using round wheels, though I don't have to say that to you Martin....

So not you-know-whose wheels, then.

Ultrascale or Kean Maygib can be relied upon to be uniformly concentric (irrespective of the wheel profile you happen to use).

[Paul Willis]

It does actually work. Note Mike's point in the instructions about using round wheels, though I don't have to say that to you Martin....

So not you-know-whose wheels, then.

Ultrascale or Kean Maygib can be relied upon to be uniformly concentric (irrespective of the wheel profile you happen to use).

"Thirty all, Venton to serve..."


Flymo