Is “in the pipeline” an AmE idiom?

Solution 1:

During a conventional war, keeping troops supplied with arms, food, and clothing has long been said to occur along a line of supply/supply line whose interruption is a primary military goal:

It appears that the plan of the French Emperor had been to strike at Prague, and establish himself on the line of supply of the Austrian armies. — William Dunlap, A narrative of the events which followed Bonaparte’s campaign in Russia, Hartford CT, 1814, 43.

The press reports indicating that the allies intend to make Saloniki the base for 600,000 men caused no pertubation in Vienna, as the entente troops will have to be met in any case, and it is argued the expeditionary forces are operating at the end of the longest, the most hazardous and most expensive supply line of the war. — The Liberal Democrat (KS), 7 Jan. 1916.

In agriculture or manufacturing, a similar logistical phenomenon may be called a chain of distribution, the metaphor usually extended by designating stations along this path as links:

It ia an interesting fact that the leading Eastern distributors favor the idea of the co-operative movement among California fruit-growers, which is now taking shape in the Fruit Union. …This corroborative evidence of the value of the movement, and the fact that the best Eastern houses declare their readiness to form links in the chain of distribution, which the Union is to forge throughout the East, should reassure the timid who apprehend that dealers’ interests will combine to crush out the growers' enterprise. — Pacific Rural Press, 5 Dec. 1885.

There are only four links in our chain of distribution — the canner, the broker, the wholesaler, and the retailer. — California Fruit News 49 (1914), 1.

First, America

In early 20th c. America, two writers choose a different metaphor, comparing the transportation of goods to water, oil, or gas moving through a pipeline:

Norway and Sweden have been gateways to Germany. Vast amounts of material, keenly needed in Germany, have reached it through the Scandinavian countries. The allies have brought severe pressure upon both countries, especially Sweden, to induce them to limit this pipeline’s operation in conduiting supplies through to the central empires. —Washington Times, 25 Oct. 1916.

I like to compare the process of distribution to the creation of a vast pipe-line leading from a great tank into which the producer pours his manufactured article.
…
Let a manufacturer move a thousand cases of his merchandise into the warehouse of a wholesaler and until that merchandise moves along the pipeline of distribution to the ultimate consumer, the only effect is to clog the pipeline at that point. — Charles Henry Macintosh, president, Associated Advertising Clubs of the World, Luncheon Address, Washington Times, 18 April 1922.

Both the extension of the metaphor in the first example to the participle conduiting and the explicit introduction of the metaphor in the second suggest that here, pipeline is just that: metaphoric language, not common usage.

Beyond these two outliers, in the daily press on either side of the Atlantic (or Pacific), the notion of a supply line as pipeline does not appear until 1942, after America’s entry into WWII, supply line remaining by far the more frequent term.

Eight pairs of shoes for every soldier is reasonable, for a pair of shoes wears out in two weeks on the desert and it takes two months to ship him new ones. There are always seven replacement pairs in the “pipeline.” — Peter Edson (NEA Washington Correspondent), Breckenridge American (TX), 1 Nov. 1942.

The quotation marks bracketing pipeline in this syndicated column suggest either military jargon, a relative new usage, or both. If it had been a common term among the American military in the First World War, however, one would expect more than a single instance among American dailies.

US Army Quartermaster Corps

Since 1775, the American military branch responsible for determining how many pairs of shoes a soldier requires under what conditions and delivering them when needed has been the Quartermaster Corps. Starting from vitually nothing when the United States entered the First World War, by Armistice Day, the corps had been equipping some 10,000 soldiers a day and shipping them to Europe. A 1946 monograph acknowledges the advantages of the pipeline concept and its general use in the corps:

But neither the initial issues nor the replacement issues could have been distributed with the speed and efficiency required by modern warfare without a certain amount of goods having been constantly on hand to insure an uninterrupted flow of the articles from the manufacturer to the soldier. This flow was described as the “pipeline” and the analogy was good, for a supply pipeline was similar to an oil or water pipeline. Both transmitted their “stocks” from the source of supply to the source of demand, and along the line certain reservoirs had to be maintained so that if, for any reason, the material temporarily stopped flowing in, the flow at the end of the line would continue uninterrupted. — Donald F. Bradford, Methods of Forecasting War Requirements for Quartermaster Supplies, Q. M. C. Historical Studies No. 14, 1946, 2.

While Bradford considers the ultimate origin of the term “obscure,” [17, note 86] he also points out that supply line as pipeline was a key concept in a study published four months before the end of the First World War, also mentioned in a Dec. 1918 history of the Requirements Division of the corps as having been authored by a “Major Griffin”:

In July, 1918, Major Griffin of the Domestic Distribution Division made a comprehensive study of the time necessary to distribute goods, and, as a result of this study, the so-called "Pipe Line" was invented… Major Griffin's study proved to everyone that just as much time was required to distribute goods for initial equipment as for maintenance and that reserves must be provided to meet initial issues as well as wastage and consumption. — A. F. Wagner, Capt., “Methods of Determining Requirements,” in Requirements Division during the World War, Philip T. Salisbury and Charles E.Coyne, eds., Washington DC, Dec. 1918, 31.

The method of calculation and the more granular statistics required by the pipeline model proved too complicated for practical use at the time, but its best features “resulted in the adaptation of the ‘Pipe Line’ idea of requirements with which every one interested in Requirements is now familiar” [Requirements, 31].

It is thus not too far a stretch to suggest that 1) the Quartermaster Corps preserved the pipeline metaphor while discarding certain aspects of Griffin’s model and adapting others, 2) that the expression remained jargon and was still in use — or quickly dusted off — when the United States entered the Second World War, and 3) that as American and Commonwealth forces began to coordinate logistics, the latter took up the pipeline metaphor and occasionally used it themselves.

Britain, Australia, and Back to America

Some six months before the Texas paper, a British daily uses pipeline to denote a military supply line by employing a simile:

As through a pipeline the supplies flow eastward. Not the least important are the squadrons of planes sent to Russia… — Birmingham Mail, 23 Apr. 1942. BNA (paywall)

This is followed by several other uses in the same year:

The Chinese situation generally has improved considerably since the days when the United Nations’ pipe-line of supply along the Burma Road was cut by the Japanese. — Gloucester Citizen, 23 Oct. 1942. BNA (paywall)

Although our pipeline has to run many thousands of miles round the Cape it is slow but sure, ... — Newcastle Evening Chronicle, 4 Nov. 1942. BNA (paywall)

On our side there is no-delay in bringing up our forces. We have an ample pipeline of aircraft coming along to replace wastage there. — Liverpool Daily Post, 3 Dec. 1942. BNA (paywall)

And also in a 1942 Australian paper:

Japan had tried to cut the pipeline between Australia and the US… Those objectives were to take Port Moresby and New Caledonia and then to punish Allied shipping with submarines and cut Australia off from supplies. — The West Australian (Perth), 20 June 1942.

Throughout the war years, there is scattered use of the metaphor:

Recent statements concerning the operational preparedness of the Americans and of the “pipeline” for aircraft, made by General Devers and Colonel Burrows respectively, afford the only clues given to the public... — Lincolnshire Echo, 27 May 1943. BNA (paywall)

If our Allies are to do their best for us as well for themselves, they must be confident that the pipeline of Lend-Lease supplies will be kept full. — Daily Record, 10 Mar. 1944. BNA (paywall)

The Luftwaffe’s front-line strength is weary and its serviceability sags. Its reserves are a mere trickle in the pipeline between factory and operating units. The replacement flow it so critically needs has been cut far below the danger mark ... — Daily Mirror, 24 Apr. 1944. BNA (paywall)

If the weather had enabled the air pipe-line of supplies and reinforcements to be kept unbroken it might have been a different story, ... — Lincolnshire Echo, 28 Sept. 1944. BNA (paywall)

And in Australia, though the second example cites a British officer, the first is Prime Minister John Curtin:

"The ever changing course of the war is a recurring check which our industries have to face in 1943," said Mr. Curtin. "The economic and industrial position of Australia underwent a revolution with the spread of war to our own country. Immediately, there was a disturbance to the flow of traffic in the Pacific and Indian oceans. To that has to be added the total demands that global war has made on the United Kingdom and the United States, and the leakages in the supply pipeline which global war inevitably causes." — Canberra Times, 19 Jan. 1943.

The personnel necessary to fill the squadrons, units and formations planned for the front line are already in the pipeline feeding air forces of the United Kingdom, Commonwealth, and Allies serving under the strategical direction at the RAF. — The Advertiser (Adelaide), 18 Feb. 1944.

Australia may have a total of £ A100 million of lend-lease goods in store, and reclaimable by the United States, or at present in “the pipeline,” en route to Australia or being manufactured for her. — Sydney Morning Herald, 31 Aug. 1945.

And back to America:

The Army Air Force is approaching peak strength—one it can maintain in combat, according to the commanding general. Pipelines of supply connect battle fronts all over the world with replacements in men and materiel from the United States. The pipelines are full.
“All we have to do,” said a supply officer, “is pump over here and it comes out over there!” — Washington Evening Star, 11 June 1944.

Lieut. Loughlin has been with the Air Transport Command which undertook the creation and maintaining of America’s “aerial pipeline of supply” across the Himalayan “Hump” in northern India. — Wilmington Morning Star (NC), 24 Oct. 1944.

The headquarters announcement said 292,000 troops are now “in the pipeline,” or in the process of redeployment to the United States. — San Bernardino Sun (CA), 16 Aug. 1945.

In the course of the war and at its end, not just supplies, but also personnel could be “in the pipeline.” The expression is expanding from a locative expression to more of a temporal one: whatever is in the pipeline is coming, but not yet. One can imagine, for instance, the desert soldiers envisioned in the Breckenridge TX article wondering when their new shoes would arrive and hearing from the quartermaster, “They’re in the pipeline!”

Post-War Years

After the war, the expression transitions from military usage such that virtually anything requiring a process to complete could be said to be “in the pipeline.”

At the end of the war a large volume of these commodities was in the “pipeline”; requisitions had been approved and contract placed but the goods were somewhere in the process of manufacture or delivery. — Survey of Current Business 26, US Dept. of Commerce, 1 (Jan. 1946), 153.

He argued that July 21 was the last date at which it would be safe to start rationing because wheat in the pipeline was declining and would get lower until the end of August. — Mallory Browne, “Commons Upholds Rationing of Bread,” New York Times, 19 June 1946. COHA

Shippers find air freight advantageous for several reasons. Insurance is lower because less handling is involved and consequently there is less chance of damage. Because of the speed of delivery it means less merchandise in the pipeline and less inventory generally for a firm. — Santa Cruz Sentinel (CA), 27 Sept. 1954.

Failure to enact even “minimum changes” in the law was termed “a great tragedy" by Roland Elliott, refugee services director of Church World Service, an agency of the National Council of Churches. The minimum changes, he said, would have meant that urgent cases “now in the pipeline” would be expedited and given visas to enter the USA under the law. — Clare Sentinel (MI), 27 Sept. 1956.

Civil rights and tax cut legislation are still in the pipeline and there is no certainty either will be acted upon this year. — Santa Cruz Sentinel (CA), 10 Oct. 1963.

Schulte, assistant administrator in the FFA’s office of General Aviation Affairs, told the Western Air Facilities Conference Saturday that “if a community plans an airport, that airport must be in the pipeline now.” — Madera Tribune (CA),17 Nov. 1964.

Twenty years before, it would have seemed odd suggesting that an airport could be “in the pipeline”: the vehicle of the metaphor, if there still is one, can be expanded from moving something from A to B to how long it takes to get here. The same transition occurs in British English:

Britain's Wholesale Textile Warehouses provide the great pipeline that speeds the flow of goods from factory to retailer in every town and village. — Western Morning News, 8 Feb. 1950. BNA (paywall)

But he warned, people must not expect these things to show In the statistics too quickly. They get into the _pipe-line and take some time to flow out. — Belfast News-Letter, 5 May 1950. BNA (paywall)

When the suspension was announced, about 200 million dollars’ worth of Marshall Plan commodities for Britain were still in the pipe-line, but not yet shipped. — Hartlepool Northern Daily Mail, 9 Jan. 1951. BNA (paywall)

With so many wage claims in the pipeline, ... — Milngavie and Bearsden Herald, 11 Aug. 1951. BNA (paywall)

The first is that removal of the tax would stimulate retail buying and clear the pipeline of supply, which has become clogged with accumulations manufactured goods. — Yorkshire Post and Leeds Intelligencer, 9 Apr. 1952. BNA (paywall)

Conclusion

In the same year, 1942, only months after Pearl Harbor, pipeline as supply line appears in British, American, and Australian newspapers. The two isolated American uses in 1916 and 1922 can merely suggest American provenance.

One is on much firmer ground, however, when the 1918 use among the US Army Quartermaster Corps enters into the mix: the pipeline metaphor, if not the exact model constructed by Maj. Griffin, appears in an identical sense twenty-six years later. The virtually simultaneous attestations in British and Australian newspapers suggest that military logistics specialists from those countries found the metaphor as apt as Bradford did and began to use it themselves. From that jargoned usage, it “escaped” into the daily press, eventually attaining common usage in every flavor of English in the idiom in the pipeline.

In those early attestations, the metaphor was more place than process: today, it can be both. A heroin pipeline is a smuggling route; in the pharmaceutical industry, a drug pipeline is the aggregate of all compounds at various stages of development within a particular company.

When money is concerned there is still some sense of the older usage. After all, one speaks of cash flow or liquid assets, so it makes sense that money can still move from A to B through a metaphorical pipeline:

At the end of the present fiscal year the military assistance pipeline will be at the lowest level in its history... The economic assistance pipeline will, as in recent years, be barely enough to keep the program flowing without serious interruption. Dwight D. Eisenhower, Public Papers of the Presidents of the United States, 1960 (1959).

If there were any American who knew about military supply pipelines, it would have been former Gen. Eisenhower, who served as Supreme Commander of the Allied Expeditionary Forces in Europe.

Otherwise, today across headlines in the Anglosphere, in the pipeline is all about plans and process:

5,000 affordable new Dublin homes in the pipeline — The Sunday Times (London), 7 Oct. 2018.

Revamp of Municipal Courts Moves Ahead, Legislation in the Pipeline — NJ Spotlight (New Jersey) 8 Oct. 2018.

Touring exhibition in the pipeline — Collie Mail (Western Australia), 7 Oct. 2018.

Plan to clean Khandal in the pipeline — The Hindu (India), 12 Oct.2018.

Major changes are in the pipeline for a proposed multi-million euro Kildare cancer clinic — Leinster Leader (Ireland), 9 Oct. 2018.

Solution 2:

Christine Ammer, The American Heritage Dictionary of Idioms, second edition (2013) has a two-definition entry for "in the pipeline":

in the pipeline 1. in process, under way, as in The blueprints for the new machine are in the pipeline, but it will take months to get approval. {Colloquial; 1940s} Also see IN THE WORKS [which has a a very similar definition and which Ammer dates to "Second half of 1900s," meaning, I think, the 1950s or later]. 2. Budgeted for something but not yet spent, as in There's $5 million more in the pipeline for the city schools. {Colloquial; second half of 1900s}

The earliest instance of "in the pipeline" in a metaphorical sense that an Elephind search turns up is from "Mackintosh Tells How to Back Up Ad Efforts at City Club Luncheon," in the Washington [D.C.] Times (April 18, 1922):

"I like to compare the process of distribution to the creation of a vast pipe-line leading from a great tank into which the producer pours his manufactured article. The first link in the pipe-line of distribution is the merchandise broker. Then there is a joint of transportation, carrying on to the second link, the wholesale house. Another joint of transportation carries that link on to the great jobbing house, and again there is a joint of transportation which carries on to the last link in the pipe line, which is the retailer. Now any manufacturer who thinks that he has moved his merchandise out of this tank along to one or the other links of that pipe i making a great mistake. Brokers, wholesalers, jobbers and retailers do not use merchandise; they merely handle it. Let a manufacturer move a thousand cases of his merchandise into the warehouse of a wholesaler and until that merchandise moves along the pipeline of distribution to the ultimate consumer, the only effect is to clog the pipeline at that point.

"The only sale that really counts is a sale made to the person who will wear the stuff out or eat it, or in some way render the reproduction of that merchandise necessary. The merchandise must pass clear out through the end of the pipe before the sale has really been completely made. At the end of the last link in this pipe line of distribution of distribution, we have a tap, and through that tap, ninety-odd per cent of all merchandise sold in America must pass and does pass into the hands of the ultimate consumer. That tap is the retail sales-person behind the counter. Experiments made recently have shown us that this tap is just 45 per cent open today: that 55 out of 100 sales made by advertising are killed by sales-people.

Although the speaker quoted in this spiel describes merchandise as moving "along the pipeline" rather than "in the pipeline," he builds the the metaphor carefully and elaborately—and the pipeline is indeed a figurative conduit for merchandise, not a literal conduit for oil, water, or some other liquid.

The next match is from 20 years later—but this time it involves use of "in the pipeline" in a thoroughly modern sense. From an untitled article by NEA Service Washington correspondent Peter Edson, in the Breckenridge [Texas] American (September 1, 1942):

Eight pairs of shoes for every soldier in Egypt ids reasonable, for a pair of shoes wears out in two weeks on the desert and it takes two months to ship him new ones. There are always seven replacement pairs in the "pipeline." Elsewhere, four pairs per soldier is enough and the demands can be cut back to that figure. The same principle applies tanks, guns, mess kits or corned Willie.

From "Changes in Air Plan: Return of R.A.F. Units in Canada," in the [Adelaide, South Australia] Advertiser (February 18, 1944), quoting the British Minister for Air, Mr. Power:

"The personnel necessary to fill the squadrons, units and formations planned for the front line are already in the pipeline feeding air forces of the United Kingdom, Commonwealth, and Allies serving under the strategical direction at the RAF. At present we have the capital and necessary immediate replacements.

From "Nazi Fighter Losses Now Exceed Output," in the [Brisbane, Queensland] Courier-Mail (April 25, 1944):

So far this year, during air fighting of unparalleled fierceness, German output has fallen below the rate of losses and is still going down.

These facts are outstanding in a graphic description of the year-old Allied assault on the German aircraft industry issued jointly by the British Air Ministry and Headquarters of the U.S. Strategic Air Forces in Europe.

Mere Trickle

"German fighter reserves are a mere trickle in the pipeline between factory and operating units,' says the statement.

From "Empire Air Training Scheme," in the Rockhampton [Queensland] Morning Bulletin (September 25, 1944):

Consequent on a reduction in intake of trainees there will be a gradual and progressive closing of a certain number of training units and schools, beginning with Royal Air Force schools transferred to Canada, and the Montreal, Toronto, Winnipeg, Clgary commands being amalgamated. The process will be deliberate and extended over many months. The personnel necessary to fill squadrons, units and formations planned for the front line are already in the "pipeline" feeding the air forces of the United Nations under the strategic direction and tactical command oi the RAF.

Although the three citations from 1944 come from Australia (reporting news from the UK or Canada), this should not be taken as representative of overall usage, as very few U.S. newspapers from the 1930s onward are searchable in free online newspaper databases.

Conclusion

Charles Henry Mackintosh of Chicago, president of the Associated Advertising Clubs of the World, referred at length and in detail to a "pipeline" as a metaphorical conduit for merchandise in 1922, but the earliest instance of a news story using "in the pipeline" as an idiomatic way of saying "on the way" that a search of U.S. and Australian newspaper databases finds is from a Breckenridge, Texas, newspaper dated September 1, 1942. Evidently the expression became common and international during World War II, but it is not clear where it originated.

Solution 3:

A similar figurative expression, “in the pipeline,” showed up at the end of World War II. A Sept. 7, 1945, article in the Times, London, refers to “purchases of all goods in the pipeline or in storage.”

Note the location London and the year 1945.

Although the phrase in its literal sense has been in existence since at least the 1890s, its usage has seen a spurt in the 1930s-40s, possibly because that was when its idiomatic use started and became popular. (Based on nGram results.)