Hi John Very interesting! From this, I deduce that: 1) Loctite is an effective insulator. 2) Most Loctite joints have metal-to-metal contact in them somewhere, as the joint gap is never perfectly maintained. The ability of Loctite-built trains to operate track circuits therefore seems to be more a matter of luck than judgement! If anyone else has done any tests, I'd be interested to hear the results. Regards Ron ----- Original Message ----- From: "John Pagett" <john_pagett@xxxxxxxxxxxxxxxx> To: <modeleng@xxxxxxxxxxxxx> Sent: Saturday, November 26, 2005 1:20 PM Subject: [modeleng] Re: Track circuiting & Loctite > Ron, > > Here are the results of my resistance measurements:- > Where possible I've allowed for meter lead resistance. Locomotive brakes > were wound well off. Coupling rods were left on! > > 5" Metro 2-4-0T - not built by myself so I can't comment on costruction > methods. Measured on complete loco. > Leading wheelset 0.1 Ohm > Driving wheelset (crank axle, pinned) 0.1/0.2 Ohm > Trailing coupled wheelset 0.0 Ohm > > 5" Sweet Pea 0-4-2 - Measured on rolling chassis. Wheels are loctited and > the driving and coupled wheels are also located by a 4BA socket grub screw > tapped into the interface between the wheel and the axle. > Leading coupled wheelset 0.1/0.2 Ohm > Driving wheelset 0.0/0.1 Ohm > Trailing pony - this is where it gets interesting - 60 to 200 Ohms. This > resistance is all in the interface between one wheel and the axle, and I > couldn't get a steady reading. I wonder if I should investigate this a > little closer? > > 4 wheel driving truck. Wheels are loctited to axles, no pins and there are > no alternative paths for the current - ball races sit in tufnol housings > and > brakes are cycle blocks. > Leading wheelset 0.0 Ohm > Trailing wheelset 0.0 Ohm > > Old wheelsets from Bromsgrove SME passenger cars - not fitted to anything > at > the moment. Wheels are loctited on but since I didn't make them I've no > idea > of the clearances involved. > Wheelset 13 0.2/0.3 Ohm > Wheelset 16 13.8 Ohms > 1st unmarked wheelset 4.4 Ohms > 2nd unmarked wheelset 4.65 k Ohms (Yup, 4650 Ohms) > 3rd unmarked wheelset 160 Ohms > > I suspect that what this tells us is that loctited wheels may be > satisfactory for track circuiting ( and they work fine for us in > practice ), > but to be really certain may require care in fitting and pins on the > interface. > > Hope this helps (he said, muddying the waters!!) > > Cheers, > > JohnP > > MODEL ENGINEERING DISCUSSION LIST. > > To UNSUBSCRIBE from this list, send a blank email to, > modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject > line. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.362 / Virus Database: 267.13.8/183 - Release Date: 25/11/2005 > > MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.