How do short runs affect locos?

[daftbovine]

Something I've always wondered about ....

 

I mainly use my car to go to the shops in and every now and then it gets a good run on the motorway to blow away the cobwebs.

 

Do locos that do short runs at relatively slow speeds on preserved railways suffer maintenance wise because they don't get the chance to do long runs at the higher speeds they may have been designed to run at?

[37114]

The cold starts is probably the worst thing for them, BR used to leave a lot of locos running. The uneven firing of cylinders during the start up puts extra strain on the crankshaft.

[298]

They seem to rot quicker as some stock doesn't run enough for fresh air to blow through and dry them out. Some lines also have issues with uneven tyre wear and paint fading quicker on one side where stock cannot be turned.

[Trainshed Terry]

And the turbos can cause problems since they only work at higher engine speeds to stop carbon build up on the impeller exhaust side.

 

Terry.

[daftbovine]

Do steam locos also get affected? I'm thinking of the large express locos that never really get to stretch their legs.

[Londontram]

With steam locos its the constant cooling and heating before and after the week ends that can do the damage as repeated expanding and contracting can cause stress and cracks, in old times a loco would have been kept in steam for weeks at a time only cooled down for major work even then a lot of work was often done with the engine still warm, on short runs some of the old style plain bearings dont warm up very quickly so the oil stays thick and dosnt flow very well making bearing surfaces wear quicker.

[Castle]

Hi All,

 

As London Tram says, the locos at Didcot have to be treated carefully when starting out and thermal cycles in the boilers are kept to a minimum with warming fires in use to bring the locos slowly up to temperature and to keep things 'ticking over' overnight. The short runs means that extra attention to fire management has to be applied. The occasional run keeping the loco in a higher cut off setting and with a bit more steam enlivens the fire and prevents the grate clinkering. When you hear the engines take the occasional 'spirited' run, the crews are not showing off! It's not so bad on the little locos (they are designed for shunting work after all) but the bigger ones do need careful handling. Oil in bearings tends to warm up quite quickly and, again, as long as things are done correctly then there is rarely a problem.

 

I hope this waffle is of interest!

 

All the best,

 

Castle

[jjb1970]

The thing that always amazes me about steam engines is the water and steam quality. On industrial and marine boilers the feed water is demineralised water dosed with corrosion inhibitors, oxygen scavengers etc and/or used with de-aeration to control corrosion. That is expensive and needs careful chemistry control but means boilers last decades and things like tube leaks resulting from corrosion on the water side are pretty rare.

[phil-b259]

The thing that always amazes me about steam engines is the water and steam quality. On industrial and marine boilers the feed water is demineralised water dosed with corrosion inhibitors, oxygen scavengers etc and/or used with de-aeration to control corrosion. That is expensive and needs careful chemistry control but means boilers last decades and things like tube leaks resulting from corrosion on the water side are pretty rare.

 

I suspect a good proportion of those systems are of the "closed loop" type where the amount of 'new' water required by the system is minimal. Under such conditions ensuring water purity is easy - its much harder and far more expensive to get the same effects on an 'open' system where large volumes of 'new water' are used (Note that in power stations the steam circuit used by the turbines is a closed loop system - the cooling water used to cool the said steam back to water again is an open system - but as it never enters the boilers it cannot cause a problem with them).

[Fat Controller]

I suspect a good proportion of those systems are of the "closed loop" type where the amount of 'new' water required by the system is minimal. Under such conditions ensuring water purity is easy - its much harder and far more expensive to get the same effects on an 'open' system where large volumes of 'new water' are used (Note that in power stations the steam circuit used by the turbines is a closed loop system - the cooling water used to cool the said steam back to water again is an open system - but as it never enters the boilers it cannot cause a problem with them).

Factories and ships also have a lot more space for filtration and treatment equipment than steam locos have.

[Peter Kazmierczak]

Just wondering if the same effects model locos?

Do those on a small end-to-end layout have different issues to those on a large round-and-roundy?

[roythebus]

Yes, on a roundy-roundy the wheels stay cleaner longer!

 

On the KESR locos that are entering service usually have a warming fire under the brick arch the day before they're due in full steam to warm everything up.

[Titan]

Just wondering if the same effects model locos?

Do those on a small end-to-end layout have different issues to those on a large round-and-roundy?

I am not sure if there is much in the way of issues as such, but it I get a noticable performance improvement after a loco has been running for five minutes or so and warmed up. On some it is sufficiently pronounced that I have to turn the controller down in order to maintain the desired speed. I think it is mostly the thin coating of oil on the gears and bearings warming up and becoming less viscous, although it is possible that a little expansion of components is resulting in more favourable clearances on bearings and so on.  I suppose potentially a good run helps to ensure that lubricant is more evenly distributed too. Whether this may or may not contribute to longer term reliability/longer life I don't know, I expect many will not run their locos long enough to find out!

[Fat Controller]

Something I've always wondered about ....

 

I mainly use my car to go to the shops in and every now and then it gets a good run on the motorway to blow away the cobwebs.

 

Do locos that do short runs at relatively slow speeds on preserved railways suffer maintenance wise because they don't get the chance to do long runs at the higher speeds they may have been designed to run at?

I used to think that this 'blowing away the cobwebs' idea was a myth; however, we had a diesel lease vehicle that was used solely to run between control centre and platforms ( a round trip of perhaps 3 km) half-a-dozen times  a day. Within a few weeks, we started getting alarms saying that the anti-pollution filter was blocked. After returning it for repair several times, the lessor gave us a petrol-engined vehicle in its place.

[Tom J]

Adding to 'Castle's comments, my experience as a young fireman on Ditcheat Manor was that unless the engine was thrashed a bit. It wouldn't steam!

[Titan]

I used to think that this 'blowing away the cobwebs' idea was a myth; however, we had a diesel lease vehicle that was used solely to run between control centre and platforms ( a round trip of perhaps 3 km) half-a-dozen times  a day. Within a few weeks, we started getting alarms saying that the anti-pollution filter was blocked. After returning it for repair several times, the lessor gave us a petrol-engined vehicle in its place.

 That would be the Diesel Particulate Filter. (DPF) It needs a good run to heat up and burn off the particles that it collects, or it will become clogged.

[ForestPines]

That would be the Diesel Particulate Filter. (DPF) It needs a good run to heat up and burn off the particles that it collects, or it will become clogged.

My car has the same problem if I just use it for tootling around town for a few months. Good excuse for a trip out to a steam railway ;-)

[Fenman]

With steam locos its the constant cooling and heating before and after the week ends that can do the damage as repeated expanding and contracting can cause stress and cracks, in old times a loco would have been kept in steam for weeks at a time only cooled down for major work even then a lot of work was often done with the engine still warm ... [my emphasis]

 

I'm not sure that was the case. There is a lovely British Transport Films documentary, Wash and Brush Up (1953), about the regular cleaning cycle for steam locos, which shows what happens to a Black 5 every couple of weeks; there is an emphasis in the film on the importance of cooling-down and heating-up being done as slowly as possible, but it is clear that everything is cooled down at every wash-out.

 

It's on the BFI's DVD collection of BTF films, in volume 4. Background info on the documentary is here.

 

Paul

 

 

Edit: And if you're too mean to buy the DVD, it also seems to be on Youtube, here - except that's an edited version.

[coachmann]

From what I have seen on preserved railways, the fire is dropped at the end of the day and re-lit next morning. I suppose it is deemed too expensive to keep a small fire in the box all night as happened in 'steam' days. Locos for boiler washout had their fires removed and were set on a road to cool down, although I believe some sheds could do warm-water washouts to speed up the process. I sometimes worked with the firelighter as shed-turner on nights and it was a long process warming up a loco from cold to minimise stress on the boiler. Looking at it the other way, after an engine has come on shed and has had its grate empties and fire mostly dropped, and was moved under it own it steam, this had to be done very carefully to prevent too much cold air being drawn into the boiler and firebox. Maybe one of the drivers or firemen on here can expand on this as it would be interesting to read a modern-day view on such matters.

[avonside1563]

At foxfield we usually put a warming fire in a cold boiler the day before and leave the fire in at the end of the day to allow a slower cooling. It's easy enough to clean the box out the following day or weekend.

[shortliner]

.......It usually means that the model manufacturers can't provide spares or replacements, 6 months down the line!

Coat on , rapid departure!

[Blandford1969]

Certainly on the SVR at the end of the day even if the loco is not in use the following day a fire is left normally at the back of the box with some at the tubeplate. The following days fireman generally tops it up so that the following morning they come to a nice backend which can be moved forwards, so making steam raising easier. Of course there are some engines which the fires always seam to go out (namely Panniers) but being so small it really makes no odds as we allow 4 hours from sign on to train (for a warm engine)

 

 If an engine is being stopped for washout then the fire is left and the engine has a couple of days cooling down before the process begins. SImilarly for an engine which is cold a warming fire is put in the previous day.

 

In terms of the lenght of time in steam thinking back when I was looking at coal consumption we had some locos continuously in steam for about 2 to 3 weeks.

 

From a practical point of view the short distances between stops means that optimum firebox temperatures and superheat are either not reached or not maintained for long periods of time so meaning efficency is lower. From the work we did we averaged the sort of effeciency a stopping frieght would achieve in BR days.

 

The lubriacating oil we use today is much thinner than that about 20 years ago, so while I cannot back it up empirically I would imagine the impact on getting bearings warmed up is now lessened. You do notice it on the first trip though of the day for about the first 4 or so miles.

[34theletterbetweenB&D]

... Looking at it the other way, after an engine has come on shed and has had its grate empties and fire mostly dropped, and was moved under it own it steam, this had to be done very carefully to prevent too much cold air being drawn into the boiler and firebox....

There is some good description of this from the steam era. Having at disposal cleaned the smoke box and ashpan, dropped most of the fire and cleaned the grate, and also filled the boiler to whatever was deemed the appropriate point for the type of loco, the loco was then in 'low steam'. Two things were vital. Close the firebox dampers so that the small banked up fire on the grate didn't burn through too fast : this of course could be a counsel of perfection if the ashpan and dampers were heat damaged or corroded to the point of not operating properly. The second was to get the loco stabled fairly smartly while there was still enough pressure to first move it (particularly a problem for locos with large superheaters which had cooled off and were now not getting any flue heat) and also stop it, because steam was used to create the brake. Holes in depot walls and heavier than desireable buffering up not uncommon, with crews having to resort to handbrakes which exerted less fiorce than a power brake.

 

Just wondering if the same effects model locos?

Do those on a small end-to-end layout have different issues to those on a large round-and-roundy?

Many any end-to-end model can be improved by giving it a long run, alternating directions occasionally. On the other hand, few are likely to wear out their pick up wipers. These are the first wearing component to need repair or replacement, in my experience of 'regularly run a distance' current RTR.

[coachmann]

There is some good description of this from the steam era. Having at disposal cleaned the smoke box and ashpan, dropped most of the fire and cleaned the grate, and also filled the boiler to whatever was deemed the appropriate point for the type of loco, the loco was then in 'low steam'. Two things were vital. Close the firebox dampers so that the small banked up fire on the grate didn't burn through too fast : this of course could be a counsel of perfection if the ashpan and dampers were heat damaged or corroded to the point of not operating properly. The second was to get the loco stabled fairly smartly while there was still enough pressure to first move it (particularly a problem for locos with large superheaters which had cooled off and were now not getting any flue heat) and also stop it, because steam was used to create the brake. 

We used the handbrake knowing that little steam was required to set a loco rolling (some of it was wasted blowing out condensed steam) but stopping it was another matter. One could have fun with engines barely in steam although it was hardly good practice and could lead to sacking. I took an Austerity 8F 2-8-0 almost to the throat of the shed complex and with the regulator open wound the reverser to just forward of mid gear and jumped off to change the points. The loco obligingly slowed to a stop further down the track and when the steam built up started to come back towards me. I climbed aboard and put it on shed using the hand brake. The folly of youth! 

[Londontram]

I'm not sure that was the case. There is a lovely British Transport Films documentary, Wash and Brush Up (1953), about the regular cleaning cycle for steam locos, which shows what happens to a Black 5 every couple of weeks; there is an emphasis in the film on the importance of cooling-down and heating-up being done as slowly as possible, but it is clear that everything is cooled down at every wash-out.

 

It's on the BFI's DVD collection of BTF films, in volume 4. Background info on the documentary is here.

 

Paul

 

 

Edit: And if you're too mean to buy the DVD, it also seems to be on Youtube, here - except that's an edited version.

As I said only cooled down for major work ie a wash out if there was a small fault a fitter would often work on the loco when still in light steam