Hornby points - Filing down the frog

[Rob-374083]

Sorry to bring up this thorny subject but there is so much information on here about points that I am unable to find anything relating specifically to my problem.

As I’ve mentioned on earlier posts, I am renovating a model railway that I built in 1991 and I am now looking at the points. I have taken advice from on here and started the replacement of some ten points using Hornby rather than Peco. The contacts seem good and the trains run over them smoothly from an electronics point of view, but mechanically they are a disaster.

It’s taken some time but I have deduced that the depth of the frogs are shallower than on the earlier points and less than the flange on the wheels of my locomotives (1991) which is causing the wheels to ‘hop up’ onto the frog and then ‘drop down’ off them and frequently derailing.

Research on the web seems to suggest that at some stage Hornby reduced the depth of the flange and reduced the frog depth accordingly. I have also read that the only solution is to replace the wheels on the locos OR increase the depth of the frog using a needle file.

Filing down ten brand new points that I’ve just spent £150 on goes against the grain, so can anybody offer any advice or comments on their own experience please.

Is filing the frogs down going to potentially cause damage and how long might it take? I haven’t a depth gauge (yet) but I’m guessing they will require reducing by about 0.25mm.

Thanks in advance.

[Topcat2018]

I can't advise on how much you need to file down the frog but I would suggest that for consistency, if you don't already have one, you should buy a digital caliper that can measure internal dimensions, external dimensions and (most important for your purpose) depth.

DON'T buy one of the cheap Chinese ones advertised on Ebay for as little as £5 as most of them are rubbish and some of them are made of plastic. I would advise buying a 6 in/150 mm stainless steel one made by Dasqua for £24.50 from RGD Tools in Mytholmroyd, either on Ebay or direct from RGD.

I might be attempting this operation myself sometime as I have a lot of older locos with deep wheel flanges but also a lot of modern points acquired from various places.

Doing this accurately with hand-held tools would be very difficult and time consuming. My approach would be to fit my small bench drill with a diamond-coated jewellery bit (basically a rotary file or grinding tool) and preset it to the correct height for taking out the required amount of material from the frog.

[Brew Man]

I have a Dremel and pillar stand accessory into which the Dremel fits. It's very good for stuff like that. It might though be worth checking out Peco Set Track points which accommodate the same track geometry as Hornby ones. You never know they might already have deeper frogs.

[atom3624]

Are you certain you need to trim the frog down, and it's not simply better fixing / location of the points, as that area might have risen up?

Trimming may make some rolling stock difficult to pass through - flanges perhaps a bit marginal.

Al.

[What About The Bee]

There is a problem with expecting your flanges to support the load in the frog, and it is inescapable. It assumes that 100% of all your wheel flanges have identical height above the drum. Why? Because as each wheel traverses the flangeway of the frog, the flange must just roll onto the flangeway, neither dropping down or riding up. 

Now let me ask you what happens as the frog wears? Eventually, the wear stops, as the drum of the wheel rides only on the rail, preventing the flange from touching the bottom of the flangeway of the frog.

Why not skip to that step directly, the depth of the flangeway of the frog should be deeper than the height of your tallest flange relative to the drum.

But Bee, won't the wheel drop into the flange gap? On the prototype, the width of the drum is sufficient to span the lateral gap. That is, the wheel rides on multiple rail head at the frog. The check rails are in place to assure that the drum of the wheel is positioned laterally over the frog. It isn't fool proof, but is much more readily accomplished than insuring all your flange heights, on every piece of rolling stock, is precisely matched to the depth of the flangeway. Impossible.

Bee

[ntpntpntp]

I can't comment about Hornby points, but I have experienced a similar problem with Peco N gauge points in that the more recent production of their code 55 pointwork seems to have reduced flange depth allowance through the frog, compared to those I built my original layout with in the mid 90s. On my most recently built module (over the past 3 years) I've experienced a few cases of "wheel lift" through the frog on locos and rolling stock dating from the 70s/80s. I ended up gouging the frog flangeways a little deeper with a needle file to match the older pointwork and to cure the problem.

It's a trade-off: manufacturers obviously want to cater for newer finer flanges on models so that they don't drop into the frog, but to be honest the new models I run on my layout don't seem to be bothered by deeper frogs.

[ModelerXYZ]

I have experienced this problem. Yes, the flangeway isn't deep enough to allow the drum of the wheel to ride over the crossing nose. This results in it riding up on the flangeway and falling off when the flange drops back to the normal depth that it would otherwise run at. I have filed out a few flangeways so that my rolling stock and locos can run through the points without falling off. Its a pain, but it doesn't have to be absolutely precise as the drum of the wheel is running on the (plastic) rail of the nose not the flangeway. In a real setting, the wheel never touches the flangeway between the crossing noses. Noses are the correct english terminolagy, the american language calls them frogs. The check rails exist to stop the wheels from sliding the wrong way and so allowing the train to fall through the track when it passes through the gap on the nose. File them down a bit, its a simple solution to the problem. Peco ones would be the same-there is not much difference in that regard.

XYZ

[atom3624]

Update from my - my apologies.

Precise opposite of what I initially thought!

I thought you wanted to file down the frog, but it's the flangeway, ensuring it's deep enough - good move and good luck.

Al.

[The son of Triangman]

Hornby R.8000 series points have shallower flangeways compared to their R.600 predecessors. You don't need to file the frogs down, just increase flangeway depth if you are using R.8000 series points and older stock. Pre-1966 Tri-ang stock will have "pizza cutter" flanges and will need flanges turning down or replacement wheelsets.

[Brew Man]

Yes, I think unless you have an awful lot of old rolling stock, I think SOT's suggestion of changing wheel sets may be the way to go.

[Rob-374083]

Thank you for all of your replies. I've a lot on at the moment and don't have time to tackle them but I'll report back on how things go.

[Kevin-377775]

I thought I had this problem but it turned out to be misalignment between the moving rail and the static rail joining the frog.

Was tearing my hair out to begin with, but I was able to tweak the points with a pair of pliers to resolve this issue...

[Simon-372339]

Are you new points R8xxxx?

The old points R612 & R613 are listed on ebay some still unused and in original packaging.

Could you return your 'new' points as unfit for purpose and get some NOS as prev mentioned?

[Rob-374083]

I purchased Hornby HT8302, being the latest version so thought I was being sensible. I think it will be a hard case to justify to a retailer that Hornby products are unfit for purpose, when the problem is current point design, compatibility with 34 year old locomotives.

[Simon-372339]

Technicalities, if you mentioned they were to run your old Hornby loco's then they would qualify as unfit for purpose.

[LTSR_NSE]

Alternatively if you feel it is unfair on retailer, you could purchase some R612 & R613 and sell your R8xxx (on eBay etc.) as almost new unwanted items.

You obviously wouldn’t get back what you paid, but you would at least have points that work with all your models & some money back for items that are currently unsuitable (for your purposes) without modification.

[Rob-374083]

That's a fair idea LT&SR_NSE. I'll look at that. Thank you.

I've made a start on one set of points so I'll see how easy it is and how well it performs.