4 Wheeled tank wagons.

[2502]

Could some one help me with the following question.We re the M/L ,Bachman ,United Molasses, Fina, Pratts,B M Products tank wagons vacumn fitted or lose fitted.

[Hatfield Shed]

My opinion is that all the older 'steam era' tank wagons on 9', 10' and 12' wheelbase chassis were unbraked, on the photographic evidence available. It apeears to be the 1957 15' wheelbase Charles Roberts design that finally introduced continuous braking to tankers. (Seems amazingly late, especially for petrol and other highly flammable organic liquids that were bulk tankered.) I'd be happy to learn more.

[2502]

That was basically why it crossed my mind.Health & Safety not invented in those days.Thanks for your comments.RON.

[1H was 2E]

That was basically why it crossed my mind.Health & Safety not invented in those days.Thanks for your comments.RON.

But perhaps it HAD been! Think about it.
Vacuum braked means brakes applied when moving. Brakes applied when moving means SPARKS...

[jwealleans]

Unless you mandate wooden brake blocks, as they did for gunpowder vans.

[65447]

A quick check of the usual reference sources suggests that, save for milk tank wagons, there was a gradual move towards faster running but that automatic brakes were not adopted until as late as 1955; the tank wagons having long wheelbases and with two stars identifying that they were suitable for high-speed running.

Prior to that, in the 1913 RCH regulations, a single star indicated that such wagons were permitted running speeds averaging 35 mph and travelling no greater than 40 miles between stops.

[Hatfield Shed]

That was basically why it crossed my mind.Health & Safety not invented in those days.Thanks for your comments.RON.

But perhaps it HAD been! Think about it.
Vacuum braked means brakes applied when moving. Brakes applied when moving means SPARKS...

May well be what lies behind it. Supporting evidence would be that tanker brakes were not be among those 'pinned down' on unfitted freights for working on banks; anyone got the relevant working instructions?

[65447]

Neither the general appendix nor the rule book make any reference at all to brakes in relation to tank wagons, flammable or corrosive cargoes, explosives, etc. and now I've found a copy the Instructions don't either.

[Seagull]

As an ex-tanker man (ships) some observations.

The most volatile cargoes (kerosine, petrol and lighter) gas off easily at normal ambient temperatures therefore you keep everything closed so your cargo does not evaporate away! The vapour pressure (pressure exerted by evaporation) by petrol in a closed tank is about 0.1bar. (1.5 PSI if you don't do metric).
The heavier grades (gas oil, diesel, fuel oil) don't gas off unless heated above ambient temperature and are fairly hard to set fire to anyway.
The exception is crude oil which containes a range of fractions and some of the light crudes can be ignited easily - though crude would not normally be transported by rail in the UK.
(They do or at least did in the US as they have extensive inland oil fields).

Normal traffic movements would cause the product to surge in the tank so the lids would be well secured - notice the tank lids have a strongback arrangement to exert an even pressure on the seal to prevent leakage.

Whatever product was in the tank wagons they would have been kept closed except when filling or emptying so I doubt very much that sparks from brakes would pose a fire risk.

Alan

[52D]

Crude was shipped from the onshore oilfields in Nottinghamshire to Pumpherston near Livingstone via the ECML during and after WW2 with a crew change at Tweedmouth. Usually a K3 job.

[2502]

Thanks for all your replies,& and as replies suggest will be leaving models as is .RON.

[Seagull]

I never knew about the Nottinghamshire oilfields before.

If the figures in Wikipedia are correct 3.5 million barrels in 2 years works out as roughly 750 tons per day.
Or more probably they were shipping roughly 1000 tons per day in the second year of production.

It is described as high quality crude, similar to Brent from the North Sea.
That would be used partly for making the lighter fractions like petrol, gas oil etc.
But more importantly you can also use it for things like lubricating and other specialised uses.

Alan

[D2100]

Whatever product was in the tank wagons they would have been kept closed except when filling or emptying so I doubt very much that sparks from brakes would pose a fire risk.

This was my (unscientific) feeling TBH, especially given that the big black thing at the front would also probably be shoving out a few sparks.

[1H was 2E]

My remarks were based on "linesiding" in the late 50's - 60's. Some, but not all, petrol tankers were clearly imperfectly sealed and a strong smell of petrol was in the air as they passed; sometimes, there was even signs of liquid running down below the cap. There were marshalling instructions regarding their position in the train, too - rule 240 (I think) in the old book - to distance them from the engine.
Even the comparatively modern tankers were not particularly well sealed; we tried to see the daily Immingham - Northampton gas train (Sahara gas to Northampton gasworks enabling the latter to be closed - this was before North Sea exploration) because it was worked by an otherwise rare 41A Brush type 4 and this train, although composed of tankers built for the job, announced its presence by a very strong smell!
But in those days, garages (as they were called then) often smelt strongly of petrol around the pumps, too.

[Seagull]

Hello 1H was 2E - sorry for the slow reply I have been a little busy.

The strong smell from most petroleum products is due to a very very small number of exotic molecules that are present in each product.
They are referred to as aromatics - with good reason. Some can be detected when they are present at levels as low as 1 part per million
(1 molecule in every 1 million).

Certain grades have a higher number of them than others. The grade that is used for diesel for road vehicles (DERV) has a high proportion.
That is why diesel is 'smelly' and also means that the staining and pungent smell are very hard to remove from clothing.

The liquid escaping I can only put down to poor maintenance and/or working practices. However the fire risk is still very small - but with correct procedures should be nearly non-existent. In order to have a fire it is still necessary to have the correct proportion of fuel (petrol vapour maybe) to air.
If the proportion of fuel to air is outside this mixture it will not burn. A train moving at any sort of speed will smell bad but the fuel/air mix will mostly be too low to support combustion.

Rule 240 mentions a barrier truck.
First thought is the as you get further from the engine the sparks would get less and smaller so not enough to ignite any part of the trailing atmosphere around the tanks.
Maybe they also recognised if a tank was next to the engine/tender that a flammable atmosphere could potentially form in the low pressure area between the tank and engine/tender rear and pose a greater fire risk. An open truck would prevent such a low pressure area forming easily so again the mixture would be too lean to burn.

A for the smell around garages. Petrol in 'those days' used to contain a high proportion of benzene which is carcinogenic.

"Funny how few old petrol pump attendants there used to be." (The quote is from the doctor on my first hazardous goods course).

Seasons Greetings to All

Alan