Stevebr

The real question is whether there is the traffic for 17 or 18 trains per hour. 3 trains per hour to Birmingham with no intermediate calls looks optimistic for most of the week post COVID if business traffic does not improve.

This is an interesting paper. The latest timetable information from HS2 is that overall, the overall time from HS2 Euston to Birmingham Curzon Street is 48.5 minutes with 2 minutes recovery time included. I enclose a simulation which I ran a while ago which shows a time of a whisker under 47 minutes inclusive of the stops at Old Oak and Birmingham Interchange which uses the characteristics of the AGV11 high speed train and the published line speed limits (max 360 kph/224 mph) and gradients. The maximum acceleration achieved was 5%g or 0.49m/s2 (4% up to 10 mph) while the maximum deceleration was capped at 4% g or 0.39 m/s2. The 2018 HS2 train technical specification requires the unit to be able to achieve a time of 45 minutes 30 seconds which the simulation indicated would require acceleration and deceleration rates of 6% g (0.59 m/s2). The 18 trains per hour still looks do-able with 17 being currently forecast with 1 spare path. Train headway is 3 minutes with every 3rd train followed by a 4-minute gap. The confirmation of a grade separation at Birmingham Interchange makes the schedule look possible. Note that for Phase 1 and 2a the maximum is 10 trains per hour.

I remember around 1992 getting a quote for a timetable graph from a company of consultants and was horrified at the price so wrote a computer program in Turbo Pascal (it was a long time ago) which did the same thing. Retiring at the start of 2021 I rewrote it using Visual Studio and used it for some work on the extended Borders Railway. Started on the timetable conflict resolution but other things got in the way! Inputs were from a train simulation package which used the unit characteristics, grades speed limits etc. Currently using it for my proposed WHL model.

Hi Jim, I would really appreciate the pdf. Steve

There is a trackplan and building elevations on Freedom of Information Request https://www.whatdotheyknow.com/request/drawings_of_mallaig_station#incoming-1745734 Apologies if this has appeared elsewhere.

Hi, The un-sprung mass will include a portion of the traction motor if axle hung. It seems that this % is between 60% and 80% of the TM weight.

Sorry the SD45 should read 1.7 tons! (axle 1325lb, wheel 1015lb*2 spur 409lb = 3764lb or 1.7t)

Hi, That's great. Not sure how I missed the Barrowmore book. I've also found GM/RC2513 from RSSB which used a Deltic to to set the standard for all future P2 calculations. (D9001? at Didcot in the early 1970's on dipped rail joint tests if I recall). This give an un-sprung mass of 1680 kg/wheel which is only 60kg/axle higher than MT25. This seems to equate to an wheelset weight of 1.3 to 1.4 tons including the spur gear. The US SD45-2 has a measured wheelset weight of 1.5 tons. Thanks for the help!

AS part of some research into rotating loads and unsprung mass I'm looking for the weight (with or without the gear wheel) of a wheelset (axle + 2 wheels) of a Deltic & Class 47 locomotive.

I would replace the 10k resistor with a 5k fixed and 5 k preset to give some ability to adjust.

Axle journal diameter not axle diameter

If I recall the B4 had an axle diameter of 4.5 inches and the B5 4 7/8”. Also in BRB speak they were the BT42 and BT45. Disk brake versions were BT21.

It’s because the power supply has not been upgraded in time. There are a maximum no of trains/hour that can run on the overhead and all the allocation is taken by the LNER. Upgrades are apparently “in progress”

I seem to recall that the BR5 bogies were fitted with 180A/200A alternators which provide output from 10mph or so

The Blood and Custard site has good info which should help https://www.bloodandcustard.com/SR-2BIL.html